The main deck on my USS Missouri is aircraft plywood you can find at your local hobby shop. This should give it a sturdy place to rest the superstructure. As for the paint give it a good sanding to get all of the bump and dips out and paint it like any other wood project. Fiberglass or epoxy the outside and inside, sand, apply primer for paint, then what ever color's you want it to be.
Also want a few coats of clear paint for protection.