Boat wrapping for the winter is very popular in Minnesota, almost the entire boat is basically shrink wrapped. I don't know what they do for ventilation, but I just know it is very common so they must be doing something right. I haven/t seen or heard of it done to an RV. However the materials a boat is made with are more resilient to the elements than the materials used in an RV. Boats are ok with water for obvious reasons, RV's are not. But I think the shrink wrapping would be a better water barrier than a cover. But I think a cover would breath and the inevitable condensation moisture would dry out faster using a cover.