We do not cover for two reasons: 1. we snowbird usually in Feb. or March and I don't want to be climbing up on the roof of the rig with snow or ice on it, and 2. we have a solar panel on the roof that provides some charge to the batteries on sunnier days.
If the roads are clear and covered with too much salt, I try to take it for a spin every month. I also run the genset at least one hour per month under load and sometimes two hours per month. The best way is to snow bird for the entire winter! I can't pull this off just yet.