From the original post, if you are "boondocking" (camping without electric hookup) only rarely, you should be fine. If you are going to boondock a lot, I'd recommend looking into a quiet camping generator.
We've camped at non-electric sites on a regular basis with one battery just fine. Friday through Sunday is no problem, even a couple more days. You have to have "battery discipline", only using power when really needed. We usually only camp like that in the spring and fall, when air conditioning is not needed (or to be more exact, wanted).
A multiple battery setup would be great, but if I was going to go that route, I would also look into a camping generator.