ABOUT THIS PHOTO:
This shows the front half of the carpeted plywood floor I built for the Subaru to correct the problems of sleeping diagonally. It extends all the way to the back end of the car. The rear portion is not visible.

At upper right is the the edge of the driver's seat. At bottom is the area of the front passenger seat. The portion with the rounded corner straddles the floor where rear-seat passengers placed their feet. The book and squeegee are above the rear bench seat. The hole is a finger hole for removing a small panel that gives access to storage beneath the plywood floor. When sleeping on this floor I had my head at this end.

To create this system I had to remove the front passenger seat and the rear bench seat. Removing and storing them them was easy.

ABOUT SYSTEM 2:
My second system came into being in mid-2005 when I built a carpeted floor that solved the problems of system1. It covered all of the rear cargo space, the area occupied by the rear seat, and the area occupied by the front passenger seat. (Removing the back seat and the front passenger seat was easy and the seats were not heavy.) It was a great improvement over the diagonal system as it allowed me to lie parallel to the car's long axis, eliminated the discomfort of the corrugated floor, and made the entire sleeping area flat. It also reduced---but did not eliminate---the need to move things around to set up my bed. Moving things out of the way got easier after I discovered that I could store some tote boxes on the hood of the car at night (a tarp kept them dry).