We just have an old futon mattress that we put on the bed of my 87 Runner. Fold up out of the way when you dont need it. I need to put a hot window switch back there so I dont have to keep crawling to the front to get out.

 

I have thought about making a camping set up for my 4runner but I enjoy my truck tent in the Tacoma so much that I have decided not to bother. I generally camp when the weather is nice and when it nice, I only have a bikini top on the 4runner anyways. I have the same Truck Bedz mattress and can say for sure that it is high quality.