Yes, the 1" plywood did come to mind. I guess I wanted to have seen it applied than go on theory. BTW Rebel Hog "TREES, WE DON'T NEED NO STINKIN' TREES"

Spur, Thanks for the idea. I was also thinking of tarp or some other leakproof layer, such as a heavy duty garbage bag. A while ago my neighbor gave me this large plastic box that expands and contracts to the length of my vans flooring. It's great for leaves and other crap I need to haul around. This may be suitable along with the tarp.