Mossy mess on faded paint

I've had reasonably good experience with bleach and water with a scrub brush (small circles with light pressure - patience will be rewarded!), followed up with a careful application of polishing compound (follow the directions and you'll be fine.) There may well be some pitting as the 'roots' of the moss will have anchored in the surface of the fiberglass over time, but the paint should clean up nicely. Seals, on the other hand, may have hardened or cracked due to their experience, but the same cleaning should at least remove the detritus and allow you to see what you're left with. I don't know of anything that will 'renew' aged rubber seals other than replacement...