Living in Seattle, I've thought about the odds of surviving a nuclear attack here. I figured surviving the blast is very possible. But after that, things look pretty grim. Long term survival in the city itself is improbable, and due to terrain there are only 3 ways out of the city. Consider that all the survivors would be clogging those routes to get to a farm, it looks like succeeding would also be improbable.
Your only hope would be to leave before the attack.
"It is the home base for the Navy’s fleet throughout West Puget Sound, provides base operating services, support for both surface ships and fleet ballistic missile and other nuclear submarines as one of the U.S. Navy's four nuclear shipyards, one of two strategic nuclear weapons facilities, and the only West Coast dry dock capable of handling a Nimitz-class aircraft carrier and the Navy's largest fuel depot. Naval Base Kitsap is the third-largest Navy base in the U.S."
The entire Western WA metro area would be completely 100% screwed. You ain't getting over the cascades in a car. You can barely get over it on a regular US holiday. Going north? Yeah good luck fighting with the 10+ million Canadians trying to come south after their own inland routes are taken over by chaos. You could maybe go South and then inland up the Columbia, but then you'd have to pass through the radioactive wasteland that would be the bombed out Hanford reservation
Your only hope would be to leave before the attack.