I just don't remember those old panels having wooden floors, but I can imagine the big problem you have. I would probably just remove every thing and install sheet metal to make the floor air and water tight. I would spray undercoating on it or spray on bed liner to do away with the tinny noise. I then would install the wood floor with stainless strips. Red or white oak would work great, but you need to use a high end boat finish all the way around to make sure the wood is totally sealed before you install it. When you are done, it will be a thing of beauty and very unusual. You may want a piece of carpet to protect it between shows and cruising, but if you have enough coats of quality finish, it will be quite durable.