Regarding using only batteries for boondocking?
If you are "new" to RV'ing I suggest you go and read and reread all the posts from the members in the "public lands/boondocking" section of this forum. It will boogle your mind all what they know about solar panels and batteries!
http://forums.woodalls.com/index.cfm/fuseaction/listings/forum/35It IS an art and constant fine tuning of banks of batteries, solar, etc etc, to get more power for their way of RV'ing. Those that are dedicated to RV'ing in this manner have 'years' of experience behind them for it to all work comfortably while RV'ing.
I envy them and am constantly in awe of all what they know about powering up an RV without plugging into a shore station! :B
That all said......get an RV with a generator installed. Because all of the boondockers have one for back up also. :W
It's kinda like we all buy flashlights to have on board and rarely use them except in an emergency situation. So as is that generator box under your coach, there to flip a switch when you need it.
Wouldn't leave home RV'ing without one.