Here is another source of RV Solar information. Go Power at
www.gpelectric.com
Solar systems of 50 to 200 watts are affordable and easy to install and will do a good job of maintaining your batteries. If you get serious and want to install a system that will power your appliances up to and including the A/C unit you can do that, but you are looking at serious cash and more than likely a professional installation. A quality generator for the latter is a much better choice.
Our newest RV came with a 80W solar system, and I am adding a 100W panel for about $120.00 for a total of 180W. The next upgrade requires a new controller and heavier gauge wires.
"The rest of the story" ... No I don't need 180W just to maintain (1) std battery. The new RV has a 12V refrigerator pulling 8 t0 9 amp when running. When we stop for a 4 or 5 hour side trip, we want to extend battery life a little.
After spending a couple of days at the Tampa RV show it is apparent that 12V refrigerator's are here to stay, the gas/electric are either a option or not available in a lot of units. There will be a interesting learning curve on how to deal with the battery issues.