Best fiberglass roof coating

Nothing.
Just wash roof

Prime it and then paint with good marine grade paint products. Saves you from fiberglass deterioration problems. It's a good do it yourself project since it doesn't have to be pretty - except for on the roll sides where it will show slightly.

Nothing

Just soap and water for me on my '03 Winnie. FYI, those front and rear cap seams have flowable silicone on them unless someone has removed it since it left the Winnie factory. Nothing sticks to silicone, not even fresh silicone.

if you look at the owners manual or go to www.winnebagoind.com and pull down the roof sealent products for re-sealing the edges. Do nothing else other than what they call for and don't paint the roof, wash it off. Dick

I used eternabond on the seams after carefully removing the previous caulk. It is not pretty but gives an almost permanent and definitely water proof seal at any of the edges, fans, refrigerator, skylights, air conditioner, antenna, running lights etc. I washed the roof really well but I didn't put any finish on it. I put Red Max Pro/Zep High Shine--on the sides but didn't want to make the roof slippery. I now take it to the car wash and wash it up before and after trips. Don't notice any need for other coatings on it.

A solid fiberglass roof may need nothing for a very long time. We Rhyno lined a rubber roof and I am sure it would work on fiberglass as well. Never leaked, climbed on roof all the time for NASCAR, and went with an off white color that maybe kept it a little cooler.