My last house, which was in a rural area, we had a 250 gal propane tank, and a 10K gal water tank. With a dual fuel generator we could hunker down for many months. The back up water pump was a 12v unit which could run for days on a 12v deep cycle battery. A small solar panel would keep it charged. When we had power outages, which were frequent due to SoCal Edison shutting of the power when the wind would blow, we would run the generator for short times so the freezer and refrigerator would cool down again. If a person got a few manageable propane tanks, say 20 gal size, and a dual fuel generator, they could site tight for weeks if they were judicious in its use.