Re: Washington Fly Fishing
Blackman's Lake just on the north side of the town of Snohomish was always a favorite of mine. especially march-May. There are a lot of holdover triploids, two boat launch areas and a park that has two pretty decent fishing piers. It's a motor free lake as well so you won't have the "zoomies" messing up your fishing although the kayaks and prows can sometimes become thick enough to interfere with casting and soaking your power bait.
Out of Snohomish there are a few others as well, on the other side of HWY 2 but south of Granite Falls, Lake Roesiger and Lake Bosworth and Lake Chaplain. In the same area are Flowing Lake, Panther lake and Storm Lake but I've never fished them.