Here's a link to an article I wrote which was just published. It lists a number of rides primarily in Eastern Washington, North Idaho and Western Montana. There's some Western Washington stuff too, though not so much. If you are looking for a ride on the dry side of the Cascades, or a longer ride that might at least skirt the eastern flank of the mountains, check out this link and the rides.
http://www.outtheremonthly.com/index.php?art=summer_cycling
http://www.outtheremonthly.com/index.php?art=summer_cycling