303 is the best, as has been noted, for vinyl, rubber, and such. They also make a Fabric Protector that is designed for things like outdoor umprellas, imagine it would be good for awnings.
There is a small but vocal cadre of owners of older, gel-coated RVs (NOT the newer ones with full body paint under clearcoat) who use a floor finish acrylic called Red Max Pro / Zep High Traffic (same product, different bottle) on the fiberglass of their coaches. Search for the threads on RMP or Zep here and on other RV forums and you'll see a bunch of stuff. It's basically an industrial floor wax for linoleum and vinyl flooring but applied to a properly cleaned and prepped 20+ year old fiberglass body, it can work miracles. Wipe on, let dry.