You would probably have to finance a floor replacement from an RV dealership
I would consider finding a contractor or some one who will do it on the side.
A RV Dealer will JACK you up!!!! (no disrespect)
They have mucho overhead and they gotta pay the bills.
If you have to replace the floor I would not abandon the tanks. They will come in handy on re-sale, even if you just leave them be.
Replacing floor is not bad if the trailer is already gutted.
Jump in there and do it yourself.
Smily