I think the best way to help you is to have you do a search for "floor repair" and "water leaks" and see what you think. Basically there are two methods for floor repair, penetrating epoxy, or cut the bad section out and replace with new wood.
Leaks can be tough, basically start with a garden hose on the bottom of the trailer and work your way up until you see water coming in.
1956 Flying Cloud
Four Corners Unit
Albuquerque National Balloon Fiesta
Vintage Trailer Academy - Formerly the original