Andy, thanks for sharing a well thought-out approach to your own circumstances.

A few thoughts on your final question: What’s the one thing I should have to be fully prepared that I haven’t mentioned? Ignoring your garden variety asteroid strike or seismic- or volcanic-induced tsunamis but considering your easterly commutes, a couple of things you may have considered, but didn't mention specifically. Enough risk to warrant planning? Your call.

— there's some history of seismic activity in the area, albeit not on a west coast scale.

— hurricanes have hit the upper east coast from time to time. Washington D.C.'s been impacted a couple of times, discussed here.

— looks like ten or so nuclear power plants around your area.

— other than "physical" terrorism — cyber-terrorism is a growing concern among some folks.