I used a wash & wax with UV protector. Not sure of the brand, got it from local RV parts store. Didn't know there were so many kinds/brands to choose from. I really wanted something with UV protector in it.
2014 Shamrock/Roo 21SSL
Complete LED Lighting
Off Road Package
2010 F250 Lariat 6.8 V-10 w/Timbren SES
Custom Tunes by 5 Star Tuning
RainX is a good idea. As long as the fiberglass is protected doesn't matter what you use. My decals on the front, script type, came off again. I think they are just staying off now. No amount of wax or sealer would have saved them.