With what you just described I would back up and say you cant have water intrusion damage everywhere so you probably have a massive moisture humidity problem. The normal thinking with a house is that you dont normally have to open windows all the time but it's different in an RV. It's just normal to have your roof vents open a small amount all the time. yes, it seems like a waste of energy but that's a minimum for trying to control the moisture build up.
It's that or run a dehumidifier. If I notice any moisture on my windows it's an indication that I need more ventilation. Hopefully that's all your problem is.