I live near Clear lake and the fishing there is good but saying it has some of the best bass fishing in Washington would be a fishing story.
Now depending on where in the Pacific Northwest like Eastern Washington or Western Washington, you are planning there is some awesome bass fishing. The Snake River has an excellent Small mouth bass fishery but best fished from a boat or a floattube. Then the Pend Oreille river has some killer largemouth fishing. But remember to get your fishing license up here the Fish and Wildlife officers will get ya, if you dont.
For both of the rivers named above i have caught some nice bass out of those two rivers.