i agree that a bike is a great backup or even primary transport. of course the perfect escape vehicle would be one of those small utility trucks like the one's often seen in some asian countries, like a little dihatsu truck with a little bed in the back. (they're about a quarter the size of a regular pickup)
found the website. maybe put slightly larger tires on it though.
http://www.daihatsu.com.my/hijetmaxx.html