In our N.W. climate winter tarping has always worked fine for us. One trick I learned is to hang 1/2 full milk jugs of water on the corners and, if long, on the middle. This eliminates the tarp flapping in the wind beating up the RV. We camp most of the year and went for a metal canopy just because it is easier to access the rig if we want to goo out. Take measurments and go with the thicker silver tarps. You will be surprised how close you can come to the right size. Just overlap what you don't use. Covering is always better than the surprise of water damage from that leak you did'nt know about Happy trails