is parked in a sunny spot on a blacktop driveway. I've had an exhaust fan running continuously in it whenever it's been plugged in ever since we got it. It had some evidence of old mildew here and there, but none since the great cleaning. I leave the bathroom window open all the time. There's nothing in there but fiberglass, so rain in there is a non issue. As a result, there's a steady airflow running from the bathroom through the trailer and out the fan in the rear roof vent. I did crack all the other windows
1/2" or so to make sure there was no stagnation during the carpet washing process.
I did, and do, have a small electronic air filter on the floor under the rear table. It dried the floor carpet out quite quickly.
The synthetic carpet on walls and floor doesn't really hold that much moisture - if there's air going over it with less than 100% humidity it will dry out pretty quickly. The problem, of course, is stagnant air.