Why not just run a dehumidifier?
I think the most important thing is to store any RV indoors. My experience comes from owning 3 used PCs over the past 8 years. I've owned an 05, 07 both from Texas and now a 2013 from Florida. The worst damage I've seen the sun's heat causing the fiberglass roof separating from the wood backing. The actual glass fiber on the roof was separating from the shell.