We bought our trailer tent in November. We aired it then but have not been able to do so since as it has either been very windy or wet. We live 2 miles from one coast and 5 miles from another. In winter the air is saturated with moisture.
We use a road cover and a winter cover, with a washing up bowl to provide a bit of a slope. My husband made a structure out of water pipe to make more of a slope. This looked like it was working as there was no water on the winter cover, but to our horror, when we took the winter cover off, there were 2 huge pools of water sitting on the road cover.
Do you think the camper will be OK? (I don't dare look!)
A transit cover is far from guaranteed to be water proof, but they usually are, unless overly worn. What Winter cover was it, as the Kampa ones are designed to be water proof, and will let water in. I habe an extra tarp under mine, for just that reason.
------------- The one good thing about being wrong is the joy it brings to others..