My general strategy for a devastating earthquake is to shelter in place; fortunately I live near a coast which gives me a lot of option.

With regard to Oregon and the CSZ, it is instructive to think how that area was reached and supported in early historic times, before the advent of modern transportation networks, all of which will likely be disrupted by the event. Goods came by sea. That would e a reasonable way of getting help to those effected by an event of the magnitude contemplated. But hopefully one would have a good two weeks or more of food available.....