I'm planning on hauling my race car with my '62 Suburban. I also use the truck as my daily driver. It's got the rear rubber/linoleum flooring over plywood. Seems to be solid all over (though I noticed it was weeping around the edges when driving in the rain).
What about just keeping it simple and putting in a new plywood floor, and then find an interior shop that can make you a nice carpeted floor cover for the back. It'll keep it quiet, look great, and won't get beat up like a race rig will when you're sliding a tool box and floor jack in it.
That's the schedule for mine. (along with some seam sealer around the edges under neath!)

Brad


SOUTHERN FALL GABfest
October 6 ~ Commerce, Georgia
Details here!


Never Pee on an Electric Fence.