"I would keep going until I found a nice state or national park campground and hang out there."
A good-sized earthquake in SoCal: overpasses down, power poles down, trees down, possible ground fissures and earth/road displacements ... I'll bet you wouldn't get all that far...
I live about 90 miles from Seattle and go there frequently for work. If a good shake hit while I was there, I figure it would take me up to two weeks to get home, because it would be on foot, with three decent rivers to cross. "Okay, guys, who's going to be the first one to test the foot bridge?"
As Lt. Gen. Honoré said after Katrina, "We need to prepare for the worst-case scenarios, not the best-case scenarios". Let's
not be like governments!
As far as most of the people here at ETS, a community shelter would be the worse-case scenario

but it's still a possibility. I cringe at the thought, myself.
Sue