A solid 12V backup system is smart. You can power a whole bunch of stuff directly from 12V, you can charge 12V with solar, wind, wall chargers, other vehicles, more.

You can harvest a 12V, large capacity battery from a lawn tractor or vehicle. If you have an inverter you can power it from a 12V battery and keep lots of things running.

If you can't have a generator, you can still use a silent 12V system like a Xantrex to keep some basic loads running at least part time.