This sounds quirky but baking pans, (get them from goodwill) filled with kitty litter, or wood stove pellets placed in several locations in the coach. I'm talking 10+ not one or two, may make a difference. Be very sure you have no water leaks. In your area you can rent a propane heater that sits on top of a 5 gallon tank. This should only be used to dry out the coach with high heat as they also create moisture. Once you get everything dried out and warm, the pans may keep the humidity within a decent level you can deal with. The small dehumidifiers can be run off a solar panel.