While there are some dollies in the Skykomish I think you'd be much more likely to connect in the Sauk and Skagit where they are present in much greater numbers. They spend most of the year in fresh water, dropping down to salt water in the spring to follow the descending chum and humpy fry and feeding there until fall when they return to the river. Most of the fish are in the rivers now and pretty well spread throughout the system. While it is legal to keep two dollies over twenty inches in some rivers (the Skagit and Sauk among them), most people let 'em all go. When I used to fish gear, years ago, I usually caught them on spoons, but they respond very well to flies and I haven't fished for them any other way for the last thirty years.