I don't worry about Zombie apocalypses nor alien invasions. Ponder them, sure, like I watch Star Trek or Walking Dead, but not take any action in that direction.
But earthquakes, forest fires, and tsunamis all happen here more than almost anywhere else and I give it some thought. Extra water, extra tools and supplies. It would take two months to get through the food stores, alone. And that's without deciding, "Screw the F&G laws, I'm There are fresh-water groundwater seeps on our beach, so that's just a scramble over the bluff. After a week, I'd get tired of that and install a well and bail out the water I needed (yeah, I've enough well screen, pipe and bailers to do that).
Like on a backpacking trip, having skills and knowledge often trump having stuff. With a doctor and an engineer, there are lot of unanticipated issues we could figure out.
One thing almost all Alaskans do in the Winter is to keep some survival gear in the trunk: sleeping bag, food and water, shovel, gloves, CCF pad, jacket, tow rope, etc. An avalanche, bridge failure, or bad accident could leave one stranded for a day.
However, the best survival gear on any road trip is a reliable car and a full tank of gas. Even running continuously, my Corolla and RAV4 will idle for over 48 hours. And in a pinch, I'd cycle it on about 1/5 of the time and have a heated shelter for over a week. The Prius cycles automatically and would automatically maintain climate control for 3 days on 10 gallons. Or much more if one manually shut it down for 20-30 minutes at a time.
As long as the engines still runs, the worst road trip is more comfortable than the best snow-camping trip – something we lot do for fun!