ABOUT THIS PHOTO:
Newly-built plywood boxes sit in my mini-van so I could see how much space they occupied. Much of my travel gear goes into the boxes. The empty space at left is used for an ice chest and other stuff. Also visible are two plywood shelves built under the side windows. Later I painted the boxes and the shelves.

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.

The boxes are nine inches (23cm) tall with lids installed. When placed in the car, they occupy a space 30 inches (0.9m) wide and 84 inches (2.4m) long. They were assembled with butt joints and wood screws: I figured they did not have to be bombproof because they just sit in place during a trip. Nylon cord acts as carrying handles and lid handles, causing no discomfort while lying atop them. The thin handles also allow the boxes to be pushed close together to make a smooth surface. In 2011 I covered the lids with indoor-outdoor carpeting to eliminate the need for the rug that protected my air mattress from splinters. In 2012 I painted the boxes gray to match the Sienna's interior. Between trips, the boxes sit in a bedroom closet.