As long as you are having them come over, go for the wash wax and roof sealant. You want the wax as it should have a UV inhibitor which will protect the clear coat. Not sure what they mean by roof sealant-- probably a liquid or spray wax. It will certainly help avoid chaulking. I wash our coach after every trip and wax it 2x a year, including the fiberglass roof. BTW- if you haven't inspected the roof, now's the time to do it. Check for cracked/drying Dicor, loose eternabond tape,etc and repair as necessary.