Wow, some very impressive platforms and drawer systems here. I sort of don't feel worthy, but mine was built for a specific purpose so I'll share anyways!
We have two large Rhodesian Ridgebacks who travel with us, so I had certain design limitations/criteria. Meet Emmett and Freya, aka the Notorious A**-Clowns. I love them like they're my children, but they definitely have more size than brains.
1. It could not be tall because I didn't want it to be more difficult for them to get in the back of the 4Runner and I wanted them to have plenty of room to be comfortable on long drives; 2. I wanted a flat sleeping platform for when I sleep in my rig; 3. I wanted tie downs so I could secure my gear in the back; 4. I wanted at least a little bit of additional storage space; and 5. I wanted it permanently mounted in the rig without any permanent modifications to my 4Runner.
What I figured out is that if I remove the rear seat bottoms (4 x 14mm bolts) and then fold the rear seatbacks forward, there was a 2 1/2" step between the rear cargo area and the seat backs. I slept on that a few times and it was long enough for me (6'3"), but the step was noticeable and uncomfortable. My plan was to build a platform for the rear cargo area that was 2 1/2" tall that would bolt in place using the existing tie-down points. Using 2x2 framing would give me 2" tall drawers underneath as a bonus. My plan is to use the drawers to hold a full set of tools for working on the rig which will be kept on board at all times.
There would be a second, forward half of the platform that would be removed during daily use, but easily installed for trips. I saw the platform @MTN4RNR built for his 4Runner and it was very close to what I wanted, so thanks for the inspiration Max!!
I started by building a frame out of 2x2 aluminum stock a friend had lying around. We carefully measured where the stock tie down points were and then designed the frame to fit. This was the rough diagram we came up with:
Then we built the frame:
That was the first day.
I took the platform home with me and built the wood platform using high grade plywood the next day. If I recall correctly, the plywood 3/8" thick. I traced the pattern of my cargo liner onto the sheet of plywood and then cut it out using a jigsaw. (Of course I had to buy a new jigsaw since my brother had borrowed mine and I didn't want to wait until the following weekend to get it back from him. New tool, yay.) After test fitting it and doing a little trimming, I then cut a piece of outdoor carpeting I found at Home Depot to size. The carpet very closely matches the color of my interior, bonus. I then cut a second sheet of plywood to match the first. You'll see why in a second here.
Then it was time to add the tie-down tracks. I used Mac's VersaTie tracks for this.
LINK I cut the tracks to length, and then drew around them on one of the sheets of plywood. I cut out where tracks were and then sandwiched the two pieces of plywood together using glue and short screws. Then I screwed the tracks in the holes I had cut out and glued the carpet on using spray upholstery adhesive. This made it so the tracks are flush and do not stand proud of the platform, making for a very comfortable sleeping deck.
I then bolted the aluminum frame in place after removing the four factory tie down points. Max had suggested mounting the platform over the existing carpet because it had noise deadener in it. Without the carpet it would be very, very loud. Then I screwed the wood platform to the aluminum frame and the back half was done!
The next step was to build the removable front section. First, I drew a high-tech rendering using CAD/CAM technology. (Is that a thing?)
It's basically a rectangle of plywood with carpet glued on and plywood stringers screwed to the bottom to level it out. I need to figure out a way to secure it in place. For now, there is a flap of carpet that covers the "joint" between the two platforms and I just screwed that into the back half of the platform.
The last step was to build the 2" tall drawers. I used 1x2 framing strips for the frame and pressboard for the drawer bottoms. The nice part is that I found pressboard with a white side which makes things easier to see in the drawers. I used hinges with paracord strung through them as drawer pulls. Here are the drawers (please ignore the zipties strewn everywhere, their bag broke open):
So, how does it work? Perfectly!! With the front section in place, I have a 6'4" long platform which is just long enough for me to stretch out and sleep comfortably. When not in use, I just put the cargo cover over the platform to protect it from the sand and water from my surfboards and wetsuits. For whatever reason, I don't have any pictures from the two trips I took loaded online to show how I secure everything and then set up for sleeping, I'll add those later.
Here's a picture from two weekends ago when I did a long day trip. I haven't yet figured out how to permanently install my CO2 air supply, so I mounted it to a board and then screwed that into the deck. The box next to it has all of my recovery gear and air hoses, etc. You can see how I used the tie down tracks to secure the cargo box in place.