While trying to find a leak last weekend, I wet the camper pretty well.
It's in the garage now. I wanted to avoid mildew, so I left it half way up to air out.
Is there any strain on the lift system leaving it in the half way position?
You will be fine. I would not keep it that way for the whole winter but what you are doing is very common. People will routinely pop up the camper in the garage a bit like you are doing after having to pack it up during a rain storm.