IMHO, if you seldom dry camp it probably wouldn't be worth the added expense, and unless you're hooked up somewhere with your own power meter you're just going to be charged a flat rate anyway. I think you need about 60 watts of charging capacity per RV battery to keep them charged during moderate use, but that would depend on what you are running. As for appearences you can mount them on the roof where they can't be seen easily but they would not be as efficient as if they where focused on the sun through the daylight hours, so then you need more panels to compensate for length of day, weather conditions, angle of sun, obstructions like trees, position of RV, etc. Lastly, if you have, say, two batteries, that's 120 watts and that would be around $1,000.00-$1,500.00 worth of solar panels if you can find them, they seem to be getting scarce lately. These where things that came up a few months ago when I was looking into solar myself so I may have screwed up the numbers a bit. I'm sure there are people out there with more technical knowledge that will be along shortly to add more info. and/or correct my mistakes.
This whole scenario changes if you're doing alot of dry camping in relatively cloud free (read desert here) areas, and you are aware or your power consumption needs. Solar power has the potential of being cheaper and much more durable than a generator in the long term, and a lot greener approach too.