I am in humid New England. In spring, summer, and fall
I keep a mini electric dehumidifier running in mine (Eva-Dry electric Petite model), prop cushions up on edge, open up all interior storage, cupboard, icebox, and closet doors, and close all exterior windows
up tight. I have insulated reflective stuff up in the windows to try to mitigate temperature swings and condensation. During the winter when the dehumidifier would freeze I park it under a roof and close everything up tight and it's fine because the winter outside air is so dry to begin with. The first few winters I put a few tubs of Damp Rid in the camper but moisture doesn't seem to be a problem if I don't do that. If I had to park where there was no electricity in the spring/summer/fall I would use several tubs of Damp Rid and keep the windows shut. Just a different way of dealing with it I guess.