The plan and practice for actually bugging out have to consider the very real possibility of traffic clogged roads, roads closed and or controlled by BG's, etc. How will you get to where you want to be? How will you get away quick enough to avoid whatever it is you are leaving to avoid? If you have family, do you have rally locations identified (primary and alternates)?
What if your route is downwind from a chemical/biological/nuclear event? Do you have alt routes or know alternate paths if you have already started on your route?
Do you realize that you probably won't be able to rely on your cell phone for communication? Even if the whole "the government has a plan to disable/take over voice comm's in the event of a serious disaster" is an urban legend, you can at least expect the lines to be clogged (anyone remember trying to make a call - especially a long distance call as 9/11 unfolded?).
I know that Jerry is looking to or has started a communications thead so this side of things will be addressed there, but....