In your case you are surrounded with a veritable maze of paved roads that can be used for evacuation. I have I-40 and route 66 which will both be clogged beyond belief in the event of a catastrophic event (earthquake, whatever). I have no choice but to use a miriad of "old" unpaved mining and back country roads to get to my Bug Out Point.

These avenues REQUIRE an off-road capable vehicle, be it 4X4 or good 4X2. A typical passenger car would never get you out. I too have pre-positioned stores which will reduce bug-out time and load bearing requirements, but if I can't get to them they don't do me any good.