We have made some of the same mods to our truck.Back when we had the Bobcat on the 06 Ford Ranger we used the rear seat area for 2 plastic drawer sets and a plug in cooler.The Next Adventures said:Modifications inside the Tundra cab were minimal. I replaced all interior lights with leds and removed the back seat. After removing the seat I put 1" thick closed cell foam across the area where the seat use to be for sound deading. Then finished it over the top with carpet. On one side of this space houses a stack of drawers that holds the majority of our clothing. This has worked out very solid and is very convenient over having bins stacked that have to be removed or shuffled around to open.
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The other side is where the majority of my tools are stored and a 14' inflatable kayak. The Dog rides on top of the kayak.
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On our 02 Tundra I also removed the rear seat and built space for 2 larger 3 drawer plastic file cabinets and a TruckFridge cooler in the middle.
All works great and gives a lot of useable storage.
Enjoyed all your mods.
Frank