In our 97 Scamp
5th Wheel deluxe the bathroom sink drain hose and faucet supply lines come through the wall that is shared with the stairs on the other side. Even if you don't have the city water connected, the lines might still be pressurized and leaking.
Have you checked the carpet under the loft bed? You might have a roof hatch or window leak, a screw/rivet or the belly band needing caulk.
Have you used the camper shower lately? It's possible the caulking in the bathroom needs replacing.
I would also check underneath the camper to see if everything is connected properly.
Good luck on your search.
Scamp 5th Wheel Damp Question:
Our 2002 5r (With front shower and wood cabinets) is extremely wet in the storage areas under the stairs and in the cubbyhole to the right.
Iíve sealed everything up and it remains wet to the touch. Is anyone else having such a problem?