Lost a car to doing this. Wonderful dry Easter weekend a few years ago turned into a downpour on the Monday morning, packed up the camper wet and set it up in the double garage at home. Got it open enough with a heater going in the garage to dry it all out over a couple of days.
Only problem was the car was parked on the street out the front, and it took all of about 9 hours before a freshly-minted P plater came screaming around the roundabout far too fast, rear ended my car hard enough to push it half up on the kerb, along with the neighbour's car parked in front of mine. Due to the heavy duty tow pack, the chassis folded instead of crumpling, and bye-bye car
Camper trailer dried out nicely with not a spot of mould though, and lived on for a few more years before being sold!