Poll needs an option D: Now that I have a van, I can have a plan.
We don't have to worry about natural disasters much here except for wildfires (central NM), but the man-made ones could be a problem.
There's a rail line about a mile from here, and who knows what is in those tanker cars, and some nearby road crossings could have DWI morons on them that could derail a train. Los Alamos NL is 80 minutes away by road, closer as the wind blows, but the prevailing winds usually would carry any airborne nasties away from us. Chances of either happening are low, but not impossible.
For practicality for getting out on trips when it strikes us, I usually keep the fuel at half a tank or more, anyway. Propane the same. If SHTF should happen, we've got our system down now, and I can water the van from a well (not city water) and we can load it for a trip from the house pantry, clothes and gear in under an hour for our typical trips. Got solar, so the batteries are always good.
I've mentally got 4 routes out by road, and another one if I had to cut fences and crash a couple gates.
So, yeah, I've thought about it (usually when I'm washing the van on Monday after watching The Walking Dead the night before), and kind of have a plan. But I don't really obsess about it. I haven't bought any MREs or 5 gallon buckets of rice or beans.
Besides, after about the first week, a zombie apocalypse wouldn't be a lot of fun any more.