Be careful with moisture or you will have a mold problem
Mold? I have so much heat in my truck its hard to imagine it would EVER get moist. Of course I understand when it rains if the wood I'm proposing to use as a floor board gets wet it COULD rot, but when I run the truck I think it will dry pretty thoroughly. That said, it would probably be a great idea to treat that plywood with the same stuff they use on pressure treated lumber when you have to cut it.
