The Festival of American Fiddle Tunes is that week in Port Townsend, which is sort of halfway between Vancouver (the one in Canada) and Seattle. From Seattle, it's a half-hour ferry and an hour's drive.

http://www.centrum.org/index.php?page=Fiddle-Tunes-WS

If you have any kind of interest in old-timey music, Fiddle Tunes is a must.

There almost certainly will be other concerts and festivals in the region related to other styles and genres, but I don't have specifics.