A technician at Forest River told me to wash the roof twice a year with a mild cleanser, Spic n Span is one recommended brand, and to check the caulking for cracks.
He said not to waste my money on products that supposedly block UV radiation.
I do have a homemade shield for the awning that I put on when the rig is parked in my driveway. The awning faces west and gets a lot of sun so I figure the 2 lengths of plastic gutter material is cheap insurance for the awning.
2015 Rockwood MiniLite 2109S
2018 Ford F150, 3.5L ecoboost
Blue Ox SwayPro hitch