Lots of good advice on batteries and how to connect them both properly and efficiently. No one mentioned cutting your load on them. Before going out and spending big bucks on four 6v Trojans (or whatever) first spend small bucks on an amp meter to measure what you've got now, then convert all the lighting you'll be using to LEDs. I think you'll be shocked by the difference just doing this alone. Then measure the current draw when you do turn other things on (fans, furnace, DC TV, etc.). You'll quickly figure out what can be used and for how long.
Once you've an idea of what you want to be able to use, you can figure out how many amp hours you'll need for the number of days you want to dry camp and if you really need to get four batteries, two or more solar panels & all that stuff. (IMHO a generator is not how you want to charge batteries.)