If I believed in the need for a SHTF vehicle it sure as heck would not be a gasoline powered vehicle. It would be an older diesel with the ability to also run on bio-diesel, I'd also invest in a small home bio-diesel brewer so I could make my own fuel.
Further the vehicle would have minimal electronic components, wouldn't want an EMP from a distant nuke to take out the vehicles electronic system.
But as I say, I don't really believe in such stuff.
Where can you get a home biodiesel brewer?