We had the same dilemma. We live in Florida and keep the PC at a storage facility. We didn't want the full body paint to get damaged by the sun so we went out and bought a cover.
After talking to folks about covering the motorhome, we decided that it would be better not to cover.
We were told that if the cover is not tied correctly, the fabric could scratch the finish in a heavy wind. So, the cover is in our garage--never taken out of the box! Tried to sell it at a good price but no takers.