Covering camper inside barn

Thanks everyone for the response! I think I've decided against getting a tarp for now. I think I will try to put some old sheets over the max air cover and roof mounted air conditioner and other vents on the roof. If it gets really nasty then next year I'll maybe get a cover. The barn is a pretty active barn with some cows in a different part of it.

Now concerning mice. I'm planning on putting dryer sheets through out the camper and a lot of mice poison. I'm hoping that'll be enough. I figure I will check it out periodically to make sure nothings getting in.