I have a Weekend Warrior Super Lite 5th Wheel. The floor was rotted away at the entrance (side) door in area about 30 by 20 in. It's a strange place since there is no plumbing there, although it...
the drain usually peeks out through the outer cover, small 1/2" flexible black but with an anti-bug deal on the end, see them all the time on new units.
We don't have much come out of these here in CA but in more humid climates you might see more condensate (the drain connects to the trough under the finned evaporator in the refer).