A lot of people don't plan for this type of thing. If you have a vehicle for a bug-out-vehicle, you should equip it for long term living.
Solar power if used correctly will be your best friend. Chard batteries, run refigerators, operate C.B. Radios and a host of other things. If you have the know how, you can run a deep well off the batteries and then recharge the batteries so you can get more water later on. I am going to put in a microwave to heat meals so I dont have to use my propane stove except on a rare occasion. If you can use the sun to geat your meals, then you will be far ahead of everyone else.