Sort of depends on just how primitive you want to go, for how long, and during what time of the year. I'd suggest doing before buying. Don't make the mistake of my parents (SOB!), who got themselves a nice generator for the back of their fifth wheel and then would up almost never using it. (My dad goes out and starts it once in a while just to make sure that it still works.)
Lynn
PS: Hey, speaking of which, if anybody wants a good working generator, let me know. My parents are getting really old; their rig is now in a yearly site near Quartzsite, so I'll bet they're never going to use their truck for much any more. Soooooo, if nothing else, I'd bet they'd be willing to part with the generator. (I know absolutely nothing more about it, and most certainly not what they'd want for it!)