After some reading (and thanks to my father in law for sending me some web sites), the final conclusion is to prepare to stay where you are, with the option of leaving.  It's better to stick close to your entire food storage, and all of your gear in a more durable location than a car.  It's also better to be close to people.  I know a lot of people have a great deal of fear of their neighbors in a crises, and it is possible that crazed mobs of looters could be a problem. But, all things considered, the best place is suburbia, far from the big city but not in the woods.  Perhaps a rural suburbia.

I've been reading Alpha Rubicon and Surviving in Argentina, and your neighbor can be your enemy and your ally.  Going to the woods is great but not practical in a hurry.  So here's what you do, depending on where you are:

1.  If you are in the middle of the city, that's probably not good.  Try to move to the suburbs, somewhere you can still commute to work but be farther from the crowds.  If you can get a backyard that's a big bonus, and you will probably have way more room for food storage.

2. If you are in the suburbs, stay there.  There are areas on the outskirts of the suburbs that are a bit more rural, and if you aren't in a house that you feel very self-reliant in, or in an apartment, try to get out to the outskirts.  You may even find an area with some farmers that are a source of food, or get a small hobby farm yourself.  An acre is enough to be self-sufficient.

3.  If you are already in the country or in the woods, you are lucky.  You've already become more self-sufficient, and if you aren't, you have more space and more freedom to do so.  

The reason you just can't run to the woods in a heartbeat, even if you already own a getaway cabin, is that you can't carry everything you need to survive long term in one carload.  You need a minimum of a year's supply of food, plus all your tools, extra fuel for your vehicle, etc.  It's a monumental undertaking and you can't just skip off and do it overnight.  This is especially so if you have children.  The other problem with owning a getaway cabin is that in bad situation other people will have the same idea as you, and if they get to your getaway cabin first, you may find yourself out of luck.

The only situations that you may need to run quickly is in the case of a natural disaster, fire or some kind of catastrophic manmade threat such as an imminent attack.  For those kinds of situations you should have a kit for your car and a supply of food that will fit in your vehicle, hopefully at least a week to a month's supply.  It's also a good reason to have an extra fuel tank on your vehicle, and maybe have a 4x4.  

I highly recommend looking into urban homesteading.  It doesn't really matter what kinds of conspiracy theories are flying around, or the political situations, or what the economy looks like.  You really can't predict stuff that happens.  It just makes sense to just be self-reliant.