We lived in a 30' 5th wheel trailer with a 13' slide for one winter while our house was being built. Typical rv trailer with 2" thick walls and R7 roof/walls and floor.
Temps would get down to zero for a couple of days with 40 mph winds for days. The colder it got the worse moisture issues were inside the trailer and especially inside the closets/cabinets.
Were first tried the vents and windows open combinations and three fans moving air but all that did was cause a very cold drafty camper.
Finally dropped by the local KOA campground and talked with a few full timers how they delt with moisture inside the trailer.
All said the same thing....get two dehumidifiers for a 30' trailer.
Worked great. These two units were whisper quiet.
It was surprising how much water we dumped daily from them.
I keep my current trailer in the trailer shed. It has one side open to the south.
I keep one roof vent cracked maybe a half inch open.
Now my son lives in FL about 25 miles from the coast. No way he could leave a window or vent cracked. He puts out a couple of containers of DampRid then checks them per instructions.
