Something like this:
http://jalopnik.com/assets/resources/2008/02/Sportsmobile_Buji.jpg

With a diesel engine in it.

Get one with a raised top and it adds more storage.

Huge fuel tanks, decent gas mileage, can live in it essentially too.

I wouldn't want to tow anything through the debris of a wrecked city. A 4x4 will help, and you can add larger tires likethat one to help ab it too.