Comparing a travel trailer to a boat is perfect. Keep the water off of the outside and the inside will take care of itself. We've trailer camped and traveled for 35, or so, years. We have never left the trailer sealed up for extended periods of time. If all of this moisture being expelled from our lungs and our pores was rotting away at the insides of our trailers, I would think that the cabinets and the upholstery would be taking the biggest hit, not the framing under the wall board or paneling. Seal up the outside, open a door or window from time to time or turn on the vent fan.
I wonder how much of this science was being pondered when I worked on the line at Santa Fe? Between junkies shooting up in the crapper, illegals jumping over the fence when "La Migra" showed up and the ex cons dodging their parole officers, I would suspect, not too often.
