I have a platform that folds on top of itself, it has reinforcement boards (playwood) that conveniently hold 3 plano boxes across the rear cargo area. The boxes consist of 1-recovery gear and compressor, 1-fluids for the rig and 1-spare parts.
I also keep many parts under my back seat. IE; axle shafts, belts, hoses, u-joints, wheel-hub
When I plan on sleeping in my rig. I remove the bottom of my rear seat and leave it home. Then I can through the boxes under it and fold out the platform. Because I have a 2-dr and my seats fold forward and with some mats to lay on there is enough room for my wife (driver side) and I me (passsenger side). I'll try and get some pictures together.