Gel coat is Gel coat whether it is on a boat or a RV. The difference is on a boat is thicker. The problem with Gel coat once it has faded, it is very hard to get the shine back. What I done with my boat because it was starting to fade was to apply some polish wax that I bought through the internet called VIP Swirl Away. It was easy to apply and remove and the shine has lasted now over two years.
Now if you have full body paint like I have on my coach you do not want to use any abrasive waxes because of the clear coat that is over the full body paint job. It would dull a full body paint if you apply harsh waxes.
I have had my coach now for ten years since new and the paint job still looks like the day I bought it. Has a full body paint with several clear coats, and all I use is a dry wash with UV protection.