ABOUT THIS PHOTO:
My sleeping bag and pillow are piled at the foot of the bed, atop the anti-sweat rug, which is on top of the air mattress, which lies atop the plywood boxes. The folded blue fabric in the window shelf is some curtains that had been covering the windows (held in place by Velcro tabs).

ABOUT SYSTEM 5:
My fifth and current system involves sleeping atop a set of plywood boxes having detachable lids. In the Summer of 2010 I built ten plywood boxes of various sizes to hold travel gear. They replace the Rubbermaid totes I had used for years. This system eliminates the need to move things because the boxes stay in place throughout a trip. It also eliminates the plywood-handling nightmare of the previous system---the lids are small enough to be easily handled and stay with the boxes.