When your MH looks as bad as mine did, you're more than willing to experiment. I had pretty much given up any hope of my MH ever looking good again. As I've said before, I've tried just about every other wax, polish, oxidation remover, gel coat restorer, etc. on the market. All of them were much more labor intensive than this project was (even including the Bar Keepers scrub). Most accomplished nothing other than a sore back & arms and a lighter wallet. A few of them (very few) gave so-so results. None of them lasted more than 2-3 weeks, and the minimal shine was gone.
It's now been a month and a half. Mostly hot SoCal sun, with a couple of light rain storms thrown in for good measure. It still looks like I did it yesterday.
I really don't think the Bar Keepers will damage graphics, even nice ones. It really is not very abrasive, more like something between rubbing compound and polishing compound. Think about this: On my metal painted cab, the finish was dull & chalky, just like the fiberglass. The Bar Keepers just gave it a deep cleaning, getting rid of any surface discoloration/oxidation/residue, etc. It left it extremely clean, but didn't leave any visible scratching.
I'm anxious to see how this holds up long-term. So far so good, and even a single touch up coat every 3-4 months (if that was required) would be a huge improvement over anything else. Yellowing (if it occurs) shouldn't be an issue for me; since my MH is tan I might not even be able to notice. So I'm real interested in others who have white coaches, to see if yellowing rears it's ugly head.