AT Overland Horizon Trailer Customization - margygreen

I purchased a 2017 model Horizon Off-Road Trailer from AT Overland ( Adventure Trailers) and picked it up on 9Nov2017. Many of the available options I chose to do myself as well as add other accessories and equipment.

The photos below show the overall exterior view. I was able to find the same factory aluminum alloy rims from partsgeek. I had three rims, two center caps, and 15 lug nuts shipped directly to AT Overland in Prescott, AZ. The tires are BFGoodrich All Terrain T/A KO2 p265/70R17 load rating C, also the same as on my 4 Runner. I haven't installed my awning yet at the time of these photos so the aluminum T slot rails are just placeholders. I also haven't decided whether I want the AT Overland Jerry can holders or something else in that space. AT Overland was out of the pneumatic tire trailer tongue jack and it was on national back-order. I will add that when it is available as it will be easier to move around on my driveway.

  • Horizon Trailer Front Left Side View

  • Horizon Trailer Front Right Side View

  • Horizon Trailer Rear View

Living in southern Arizona and camping throughout the southwest I value shade when camping and wanted a larger awning. The awning bracket is from Expedition Outfitters and designed to hold the AluCab Shadow Awning or an Eezi Awn Manta 270 awning. At the time of this writing only two of these brackets for the AluCab on a Horizon trailer exist, mine and the owner of expedition outfitters.The advantage in my opinion of this awning bracket regardless of which size/brand awning you use is that it can fold over when driving so the awning is not sticking out on the side. As an engineer I appreciate this concept and design. The bracket is laser cut stainless steel and I added the blue edge guard on the top edge on the kitchen side. The AT Overland Rails for mounting the tent are asymmetrical. They were mounted with the long side on the right. To provide clearance when opening the tent with this fold over awning bracket installed, I flipped the tent support rails putting the shorter overhang on the kitchen/awning side and adjusted the position of the tent. The tent can easily be opened and closed easily clearing the awning bracket after this change. Before the switch it barely cleared.The diagram from AluCab shows the open dimensions of the awning. The awning is available in both Left and right hand opening designs. Mine is the right hand (US passenger side coverage).

  • Folded Over Awning Bracket

  • Awning Bracket with Edge Trim

  • AluCab Shadow Awn Dimensions

  • Hinge Side Awning Bracket

  • AluCab Shadow Awning Upright

  • AluCab Shadow Awning Folded Over Stowed Position

  • AluCab Shadow Awning Upright Backside View

I added amber LED lighting to the underside of the three main arm rails. Each arm has 6 feet of LEDs with the center rail having slightly more but it is separated to accommodate where the leg attached to the underside of the arm.The switch is inside the kitchen box side (shown further down on this page). The wiring is attached using quick connect SAE cables. The main cable plugs into a waterproof port at the back of the kitchen box. Currently a 1 to 4 SAE plug adapter is shown but I will switch that out with a 1 to 3 cable since the three rows of light are enough and I didn't need to add any additional LEDs to the underside of the awning case as originally planned. Also not shown is the 2 inch wide 3/8 inch thick weather strip I installed on the back side of each vertical post. This protects the tent cover when the arms are folded over.

I attached a track that fits keder rod on the underside of the awning to hang the roll-up utensil kit I made.

  • AluCab Shadow Awn amber LED lighting - Front Angle

  • AluCab Shadow Awn amber LED lighting- Rear Side View

  • AluCab Shadow Awn amber LED lighting - Rear View

  • Awning LED Light Power Connectors

  • AluCab Shadow Awning Amber LED Lighting

  • Awning LED Lighting Power Port

For the nose box I only had AT Overland install the two 105mAh batteries. I installed the batteries in parallel to increase the available mAh at 12V. AT Overland also installed the electric brake controller.  I installed the other additional electronics. I installed a warm white LED light at the top front of the box. This and all other trailer mounted LED strip lights are attached first to an aluminum channel that holds the strip at 45 degrees and has a diffuser. ON the left side of the box I installed a NOCO Genius GCP1 AC shore power port and an Optimate 0-20 SAE Solar Panel port.  The AC port connects to a NOCO Genius  Gen 2 20 Amp 2 Bank battery charger which in turn connects to each battery. The solar port connects to a  Morningstar Sunsaver TrakStar 15 Amp MPPT Charge Controller 12V/24V. A 200W P3 Solar panel described in detail on another page connects to the solar port. On top of the Nose box lid I installed a GANZ Eco-Energy Semi-Flexible 12W Solar Panel to trickle charge the batteries via the solar controller so the trailer doesn't always have to be plugged into AC when not in use. This solar panel is very durable and typically used on sail boat decks and can be stepped on.There is also a Blue Sea Systems 12 circuit fuse box. It is connected as a load to the solar charger. This prevents anything connected to it from running down the batteries using the solar controllers minimum battery voltage control.

I also covered the positive side of the batteries with a square of 1/8" thick rubber as an extra safety precaution against a metal to metal (+) post contact. The extra space in the bottom is also used to store a small extension cord, potable water hose, and a 12V DC shower head (all in custom sewn blue ripstop nylon bags).

  • Solar Panel and Shore AC Power Ports

  • 12W Solar Trickle Charger

  • Nosebox Electronics and Batteries

I installed aluminum L angle to create a shelf in the nose box. All hardware used is stainless steel to prevent rust. I made wood platforms from 1/4" maple. Spacers hold the panels in place but also provide an air gap down the center. The upper level holds the sink and sink hose, the collapsible dish pan and bucket (used to collect sink water), my dogs food and water bowl, a saw, and wheel chocks when driving.

  • Nosebox LED Lighting

  • Nosebox Shelf

  • Nosebox Shelf Storage

I installed a Rigid Industries A series warm white led light on a 30 degree mount above the sink. The light is controlled  by a switch in the kitchen box. I also attached the stopper to the sink using a stainless steel bead chain. I sewed a cover for the  manual faucet so it doesn't get covered by dust and mud when driving. After our first try out camping trip, I decided to add the aluminum shelf bracket on the side of the nose box to hold a shelf. I made the shelf from maple plywood and sealed it with matte outdoor poly. The shelf support is attached via a short section of piano hinge. This holds the dish pan with soapy water at a  comfortable working height when doing dishes and the sink is used for rinsing. When camping a towel is placed over the nose box solar panel and a folding drying rack is setup on top of the nose box lid. Due to a curvature in the nose box side panel and the requirement that the shelf support not have any curvature,  I had to reinforce the shelf bracket with a 1/4" thick aluminum strap on the exterior and interior. I purchased two 11 lb (half height) propane tanks and brackets and installed them myself (modification of bracket required details here.)


  • Right Nosebox Propane Tank, Sink & Shelf Mount Rail

  • Sink

  • Rigid Industries A Series Sink Light

  • Nosebox Side Shelf

  • Nosebox Side Shelf Showing Support

  • Nosebox Side Shelf Showing Support

  • Chained Sink Stopper

I replaced the water tanks bottom drain plug with a lever valve. To protect the valve from rocks I installed a steel plate. I put an edge guard on the edge to protect hands from the metal edge. I also made a removable spigot that attached to the drain so when camped I can easily get a larger volume of water from the tank at once to fill pots.


  • Rock Protector for Water Drain Valve

    Rock Protector for Water Drain Valve

  • Rock Protector for Water Drain Valve

    Rock Protector for Water Drain Valve

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The right side box is used as the Kitchen. I didn't want the stove attached as I prefer to cook a little away from the trailer and also to avoid splattering the kitchen box. I set the stove up on a table next to the kitchen and sink. The power center has a 2 port (2.1A each) USB outlet and switches to control the LED lights: Box warm white LED, Rigid Industries A Series exterior sink light, and an Amber LED light for the awning. The LED lights are Supernight 5050 Outdoor strip lighting. I've been using Supernight LED strips for many years and have never had any problems with failures. The flip cover switches prevent them from accidentally being turned on. The LED light located in the two side boxes and the main cargo area are also on an aluminum channel that holds the LEDs at 45 degrees and has a diffuse cover. I made labels and other vinyl cutout stickers with my Cricut vinyl cutting machine.

The contents of my previously discussed Camping Kitchen Box are all now in the right side kitchen area of the trailer.

  • Right Side Kitchen Box

  • Kitchen Box Electrical Switches and USB

I don't like the size or construction of a Trasheroo so I got a Spare tire bag from Blue Ridge Overland Gear. I added a grommet hole in the bottom for drainage and the patches. The bag is the perfect size for me and attached perfectly to the side of the tire leaving the spare open for a Yakima Spare Ride tire mount bike rack.

  • Spare Tire Mount with Yakima Bike Rack and Trash Bag

  • Blue Ridge Overland Gear Trash Bag

  • Trailer Trash Bag Patches

The main box holds the National Luna Weekender Twin 50 L Fridge/Freezer I purchased from Equipt1. I covered details about the fridge here.  It is on a Tembo Tusk slide installed by AT Overland. The slide is larger than the fridge to allow for enough clearance to slide out and open the lid. Originally I useed aluminum Zarges box(s) next to the fridge to store food and other gear. However once I figured out what I want to put in the trailer I added drawers (See further below). There is also a warm white LED light and switch installed in the main compartment. I welded and installed a barrier behind the fridge so gear doesn't slide into the space when it is pulled out. I would have built a cage around the rear and side if I didn't have plans to add drawers. The yellow tube is the P3 200W Solar Panel EZ-Out System previously discussed here. And my navy trailer Crocs because they are comfy to wear around camp after removing hiking boots.

  • Main Cargo Compartment

  • National Luna 50L Twin Weekender Fridge/Freezer

  • Rear Fridge Cage, Trailer Crocs, & Solar Panel

Why yes you can add a Tembo Tusk pull out cutting board under the fridge slide on an AT Horizon trailer. All you have to do is off set the pullout mounts to the left to clear the rear trailer door latch and drill new holes. This provides a platform to place items when rummaging through the frig or a table for a quick roadside lunch.

  • Tembo Tusk Cutting Board Pull Out. Offset mount on AT Horizon trailer.

  • Tembo Tusk Cutting Board Pull Out. Offset mount on AT Horizon trailer.

  • Tembo Tusk Cutting Board Pull Out. Offset mount on AT Horizon trailer.

  • Tembo Tusk Cutting Board Pull Out. Offset mount on AT Horizon trailer.

  • Tembo Tusk Cutting Board Pull Out. Offset mount on AT Horizon trailer.

  • Tembo Tusk Cutting Board Pull Out. Offset mount on AT Horizon trailer.

I wanted drawers in the main compartment next to the fridge/freezer. I received the custom aluminum drawers I ordered from Highway Products in Oregon. The bottom drawer is the full length of the cargo area and the upper drawer it about 32" and will go back almost even with the rear fridge barrier. I didn't want the upper drawer to be full length as I needed that rear storage space for my P3 solar panel, ground mats, chairs, & tables.

I had to remove and trim the rear cargo fridge barrier I made to allow for the top drawer to clear. After touch-up painting and plastic end caps were installed on the cut tube the barrier was reinstalled.

The interior dimensions of the drawers are: (L x W X H in inches)

Bottom 50-1/2 x 12-1/4 x 8-3/16

Top 29-7/8 x 14-1/2 x 10-7/8.

The drawers are not the same width to maximize the interior storage space given the required clearances. The top drawer also had to be shifted over and back slightly to clear the wire door support bracket and provide interior clearance for the locking T handle. The shorter height on the bottom drawer was required to allow the needed space in the open rear storage area.

The drawers are made as two independent units sitting on top of each other. They are bolted down.

I use the top drawer for food and it precisely holds three plastic tubs to organize meals and snacks. The bottom drawer holds gear.

We use the left box as our dresser to hold clothes and personal kit items. This side is on the tent opening side and is accessible from the tent room. I installed a warm white LED light (Supernight 5050 Outdoor) with switch and a 2 port 2.1A each USB outlet. This light and the kitchen box light are mounted on a 45 degree channel with diffusing panel and are positioned to fully illuminate the fold down door.

  • Left Side Dresser Box

  • Dresser (Left) Box Light Switch & USB

I added a shackle to the rear receiver to aid in recovery if needed. I can also tie my dog leash here too. The suspension is the AT Overland independent Trailing Arm Air Suspension TAAS 4.0 with a Rancho 9000 shock and airlift air bags. There are two air inlets on the trailer tongue to fill the airlift bags. (I need to make a new sticker as I put it on crooked and its bothering me.)

I would like to add a Rigid Industries LED backup light.

  • Rear Shackle

  • TAAS 4.0 Suspension

airlift shock air ports

The trailer is outfitted with an Eezi-Awn Globe Tracker trailer tent. AT Overland did the installation but Eezi-Awn products are imported into the US by Equipt1. The front room is 83" x 93", plenty of room to comfortably escape weather. The room can be completely removed just leaving the overhang roof. (I suggest staking down the corners in case a gust of wind comes up if you do this.) I wrapped the ladder with 5/16 inch rope so it feels better on the feet.

The advantage of the trailer tent is that you have full access to the left side box on the trailer which we use as a dresser. An access panel unzips on the tent's room wall so you can get to the side box. With a regular roof top tent, the tent would fold over into this area and you would have to stoop over to get into the side box. I went back and forth debating which tent to get but side box access was a main driver as well as a thicker mattress. My dog can also sleep in the room where previously she always slept inside ground tents with us. Not sure her or I like that but on our first trip with the trailer she got skunked so we were glad she was down in the room.

Since the mattress doesn't fold up it is thicker at 3.5 inches. The mattress is specified as Queen size but in reality it is 55 inches wide x 79 inches long. I currently have a queen size mattress protector, flannel sheets, two down pillows, and a heavy ultra warmth fill down queen comforter. The comforter is smokey blue and is from The Company Store (one of the very few places to get real down comforters available in colors versus white). The bedding stays in the tent when it is folded up. In colder weather we will put our down sleeping bags under the down comforter if needed. In warm weather swap out the flannel sheets and use a fleece blanket, however since I am a cold sleeper I will still have the down comforter available to pull up except in the hottest summer weather.

To brighten up the boring khaki, I  just sized and hemmed two pieces of colorful batik print fabric that are draped on each end over the roof bar. The ends are held tight by themselves but at the center the two pieces are held tight and together by two diaper pins. Now it is much more cheery.

  • Eezi-Awn Globe Tracker Trailer Roof Top Tent Deployed

  • Eezi-Awn Globe Tracker Trailer Roof Top Tent Deployed

  • Eezi-Awn Globe Tracker Trailer Tent Interior

  • Eezi-Awn Globe Tracker Trailer Roof Top Tent Batik Roof Print Panels

  • Eezi-Awn Globe Tracker Trailer Tent Interior

  • Eezi-Awn Globe Tracker Trailer Tent Interior - After Ceiling Panel

  • Eezi-Awn Globe Tracker Trailer Roof Top Tent Batik Roof Print Panels

I finally decided to get the AT Overland can holders. On the drivers I keep a NATO metal gas can. On the passenger (trailer kitchen side) I have a Sceptre military water can for drinking water. I have an extra NATO strap for the holder so the trailer can carry two NATO gas cans instead.

  • Replaced pads with thicker 1/4" for Dinuba Water Can. AT Overland NATO can holder.

    Replaced pads with thicker 1/4" for Dinuba Water Can. AT Overland NATO can holder.

  • Gas Can. AT Overland NATO Can Holders

    Gas Can. AT Overland NATO Can Holders

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Since the AluCab Shadow awn prevents the use of some of the roof top tent fly rods, I devised a method to still hold the fly out. For the three rods on the long side next to the awning I riveted a vibration dampening clamp to the top outside of the awning in a location that would align with a shortened rod. I didn't want to modify the original Eezi-awn rods so I ordered a pack of eight Tepuli replacement roof top tent rods. I checked the various RTT companies and Tepuli was the cheapest for replacements. I welded washers to the curved end because of the new rod angle the fly would slip down the rod. I determined the required rod length and added any needed bends in the rod.  One fly rod on the rear side needed shortened. For this one I riveted the clamp onto the last fold out segment of the awning in a vertical position.

Since the new rods are different lengths and shapes, I color coded the rods and tied the matching color cord to the tents rain fly loop.

While the 3.5" mattress is nice and comfortable, I'm a bony side sleeper and wanted a little extra comfort. I added a queen size 1 inch thick soft latex mattress topper from Sleep on Latex. This added just the right amount of additional comfort I needed.The mattress and topper are covered by a waterproof terry mattress protector. Even with the 1 inch topper and bedding the tent still folds up and the cover fits. The topper is slightly bigger than the mattress but I didn't need to trim it. The African animal print on the original mattress is shown in the first picture below.

AT Overland sent the pneumatic tongue jack when it came back in stock so I swapped out the rigid tire jack to the pneumatic jack. The tire is much larger and easier to maneuver. However, I'm going to keep the rigid hard wheel to install when the trailer will be sitting between trips so the pneumatic wheel doesn't get compressed in the same spot. It is an easy swap out. If the trailer is not connected to a vehicle I just use a jack stand to support it during the exchange.

I was concerned with rain getting into the side box along the top opening due to the length of the door in sideways blowing rain possibly funneling water into the gap. I solved this potential problem by installing a Trim-Lok Drip Rail. This is a flexible PVC rain gutter designed for RVs. It comes in black or white. To create an even better waterproof seal around the top and two side edges I also caulked the space with 3M UV 4000 marine adhesive caulk. This has been the perfect solution and so far has held up in light rain and a heavier hose simulation. I went a head and added the drip edge to both side boxes. The photos below show the drip edge after my hose rain test. You can see that the curved bottom of the rail also pulls the lowest point away from the door panel preventing drips from entering the gap.

Build Pictures from AT Overland

Adventure Trailers (AT) Overland in Prescott, Arizona provided the pictures of the build. I was able to find the same factory aluminum alloy rims from partsgeek.com. I had three rims, two center caps, and 15 lugs nuts shipped directly from parts geek to At Overland. The tires were ordered online and AT Overland had them installed on my rims. The tires are BFGoodrich All Terrain T/A KO2 P265/70R17 load rating C to make the tires on my 4Runner.

The chassis shown (with other shop tires) was built and the wiring for DOT required ligting installed. The white box is for the main storage compartment. The three cargo boxes have been installed in the last picture.

  • Horizon Chassis Built
  • Trailer tires & rims to match 4 Runner
  • Horizon Main Cargo Box
  • Horizon Trailer cargo boxes installed (shop tires not mine)

19 Gallon water tank installed with manual faucet. removable sink waiting to have it's bracket installed. Rear before swing out spare tire holder is installed.

  • license plate light being installed
  • water tank installed, sink mount waiting to be installed
  • rear before spare tire hodler installed

I made custom accessory shade panels from 87% shade gray panels. The edge of the awning has 2 inch loop Velcro. This is used to attach the panels. The large panel can be extended out with poles to make a huge shade area. Two smaller shade panels can be moved anywhere along the awning perimeter to provide shade or a privacy screen.

  • shade panels_14Jul2018_002
  • shade panels_14Jul2018_005
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  • shade panels_15Jul2018_014
  • shade panels_15Jul2018_016
  • shade panels_15Jul2018_019
  • shade panels_15Jul2018_024

For more information on individual components or  other camping gear and truck modifications check out the upper level link:

http://www.margygreen.com/Blog-Adventure


Photos in Action

  • 2004 Toyota 4 Runner & AT Overland Horizon Trailer. Sierra Nevada Mountains, Mono Co., California CA United States
  • campsite, Mono Craters, Mono Co., California CA United States
  • campsite, Mono Craters, Mono Co., California CA United States
  • campsite, Mono Craters, Mono Co., California CA United States
  • 2004 Toyota 4Runner. Pinto Mountains, Riverside Co. California USA
  • 2004 Toyota 4Runner. Pinto Mountains, Riverside Co. California USA
  • campsite along Joshua Tree N.P. Border, Eastern Coxcomb Mountains, Riverside Co. California USA
  • Eastern Coxcomb Mountains, Riverside Co. California USA
  • campsite along Joshua Tree N.P. Border, Eastern Coxcomb Mountains, Riverside Co. California USA
  • Eastern Coxcomb Mountains, Riverside Co. California USA
  • campsite. Pinto Mountains, Riverside Co. California USA
  • campsite. Pinto Mountains, Riverside Co. California USA
  • campsite. Pinto Mountains, Riverside Co. California USA
  • 2004 Toyota 4Runner along Joshua Tree N.P. Border, Eastern Coxcomb Mountains, Riverside Co. California USA
  • 2004 Toyota 4Runner & AT Overland Horizon Trailer. Ancient Bristlecone Pine Forest, Inyo Co. California USA
  • 2004 Toyota 4Runner & AT Overland Horizon Trailer. Ancient Bristlecone Pine Forest, Inyo Co. California USA
  • 2004 Toyota 4Runner & AT Overland Horizon Trailer. Ancient Bristlecone Pine Forest, Inyo Co. California USA
  • campsite, Alabama Hills, Inyo Co. California USA
  • campsite, Alabama Hills, Inyo Co. California USA
  • 2004 Toyota 4Runner. Alabama Hills, Inyo Co. California USA
  • 2004 Toyota 4Runner. Alabama Hills, Inyo Co. California USA
  • Camp Guard: Pixelated jaypeg, spinone italiano. Yeager Canyon, Coconino Co. Arizona USA
  • Brushy Basin, Yavapai Co.Arizona USA
  • 2004 Toyota 4Runner along Joshua Tree N.P. Border, Eastern Coxcomb Mountains, Riverside Co. California USA

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