Hypothetical worst case
My neighborhood just north of DC is unlikely to be survivable- I am building a shelter in the basement, but it feels foolish to do that- mostly its something to do, I guess... Of course in reality the best thing to do is probably drive to ground zero if you have time.
If things start escalating my best bet is to find a place to hole up far from ground zero and fallout- assuming you have time and realize the threat before everyone else does and the roads are clogged.