Rain, Leak, Dicor but... what happening in walls?

You may think this is extreme but it WILL work.
Do the dehumidifier.
Drill a few 1/4" holes along the floor (inside)above the bottom plate.
Turn furnace on about 90*.
Set a good fan blowing toward the wall at the holes.
Let it do it's drying for a few days.
Your Trailer will think it has been to Az.

PS: This will also dry the carpet and floor.