RV repair tech told me that having condensation on the windows means there is also condensation inside the walls, you just can't see it.
Condensation is a product of more moisture than the atmosphere can support, there's a bunch of variables behind it. Cracking the windows and roof vents NEVER worked for me, especially since I use my RV's kitchen a lot.
I purchased a Frigidaire 70 pint dehumidifier and leave it on if I'm at a CG with power, or run it occasionally if I'm bookdocking. It's amazing after running for a few days the gallons of water that I dump out. One of these days I'll drill a hole in the belly and run a drain hose for it.