[RMcNeal]

If you would like to stay maintenance free, look for AGM batteries, rather than flooded cell. They are more expensive. If you are like me and do not boondock, and do not have the residential refrigerator (I do), you probably will be fine with 1 or 2 12 v batteries instead of 6v. The AGM batteries are much more expensive than flooded cell, but do not require any maintenance. It really just depends on your needs. I just recently decided to go with 2 12v AGM batteries since my coach has the residential fridge running on an inverter during travel. The single battery CW put in is not keeping up on hotter travel days.
If not for the residential fridge, I'd have gone with a single 12v battery. No need for anything more since we never boondock.