Back when we had no inside storage, I used a medium-weight farm tarp purchased from a nearby farm supply store. I bought the size that would cover the side too down below the windows. I added double the amount of grommets and used elastic cords to keep the tarp taut at all times. I never found any wear spots from tarp movement by wind. Each tarp would last 3 years, once in a while 4. The air conditioner and vents will maintain an air space on the roof adequate to prevent mold/mildew.
2000 Winnebago Ultimate Freedom USQ40JD
, ISC 8.3 Cummins 350, Spartan MM Chassis. USA 1SG, retired;PPA,Good Sam Life member."We the people are the rightful masters of both the Congress and the Courts - not to overthrow the Constitution but to overthrow men who pervert theConstitution. "Abraham Lincoln"