A thought on mileage: you know your highway and city mileage, but bug out mileage might be more like stuck in rush hour from hell mileage, or back track a lot mileage.
If I had a Morrow Project grade hideaway somewhere, I would stock it with diesel fuel and diesel powered equipment, including at least one Lister generator. Lister is an old, incredibly reliable diesel engine. I am sure it is not CARB compliant. Lister is still used in lifeboats, and for emergency duty on modern ships. I have worked on ships that used Lister powered generators for emergency power to the radios & boat deck, or Lister powered compressors to provide air to start other engines from a black-ship condition. They are heavy for their output (+/- 1000 pounds for a big 20 hp 2 cylinder), but can be hand crank started, or started with a hand pumped hydraulic motor. I have done both. Diesel fuel is more shelf stable than gasoline, and as was said above some diesel engines are tolerant of a wider range of fuels, from soybean oil to used motor oil.
A modern diesel engine with high efficiency electronic controls will run great until you make it drink something it doesn't like, or it blows a module. Then you will need a Borat horse to pull your rig.
Sean mentioned screwing mesh over the windows. Clear packing tape or other adhesive film on the windows can reduce the shower of broken glass if windows are broken. Most of us keep a pair of sun glasses in the car, but a pair of safety glasses or goggles could keep you going if windows are smashed.