It's hard to beat a pickup with a camper shell or a good SUV as a bug out vehicle. What works for a long camping trip is going to be ideal for evacuation.

The best bet seems to be to shelter in place as long as you can and only evacuate if you have to. If it is not the EOWAWKI water and supplies will be trucked into cities until utilities can be restored.

What may be desirable is a radiation shelter in case of a nuclear explosion. The blast radius is not as large as we have been let to believe and the radiation drops down to non-lethal levels within a few days.

The biggest PIA would be if the authorities required you to evacuate. Stores would be cleaned out in all directions out of any large city. The group shelters, in the case of a large event, would not be fun. The authorities may not give us an option of where to evacuate to.