One pretty good cleaner for gelcoat is Lime Away - mildly acid with good cleaning characteristics .. Scrub the thing 2x and rinse very very well .. Yes Bartenders Friend for " trouble spots ." - but only Trouble Spots.
Then consult Consumer Reports About Car Wax / Polish .... I have been using NU FINISH for yonks on both my fiberglass boats , Scamp
and vehicles. Works for me at a reasonable price.
( I am frequently amused with the praises of Cabana Wax as an ingredient - Cabana Wax is derived from the Cabana Palm and has the interesting of melting at body temperature ... We have eaten lots of it as the coating of M & M's - which melt in your mouth instead of ...... ! Ya Pays your $$ and takes your pick ! )
Remove the Decals with a wheel - about 10 bucks on ebay - very easy and clean . If replacing the Decals - and having them made - consider using the 3M reflective decal material - it is of heaver weight
- lasts a lot longer - and finding ones home in a campground is a reflective experience .
All the Best