I live in Michigan. We get a lot of snow each year. This past summer I went to the marine Store and asked for the best boat wax they had. I also bought a motorized polisher. I polished the entire RV and them applied 3 coats of marine wax on it. I also spent 80 hours underneath the RV and used a combination of POR15 and a spray rubberized undercoating paint to protect the entire underside of the coach after I did a good cleaning with a power washer.
It's sitting out side with a bunch of snow on it, (I don't have a pole barn for it) but I can tell that the wax protection is helping as it still shines in the sunlight, although you still get the black marks from water draining on the corners.
When I leave for Florida I will take it to a truck wash before I park it for my stay. On the way back I don't think snow will be a problem by that time.