If you come into Seattle, you will be coming into Seatac Airport, about 30 minutes south of Seattle. Parking in Seattle is a B*&^% now in the downtown area, and expensive, thanks to the progressive mayor, but that's another issue for another day. The test is usually given at the Seattle Center, about 2 miles north of the main downtown area, where access is pretty good and a parking garage to the north with a moderate fee.
In eastern Washington, I would expect the exam to be in Spokane, but I do not have any lead where. Nevertheless, in general, Spokane is pretty open and easy to maneuver in with parking readily available and not expensive from what I remember.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask