As someone said most of the cutts are done in the salt. Not sure how you feel about the drive but the N Fork Stillaguamish is an excellent dry fly river for Cutthroat in October. It is catch and Release only on everything except hatchery steelhead and is fly fishing only until Dec 1.
Use Size #6 and 8 Humpies, Royal Wulff, Caddis, Spiders, Reverse Spiders, and Clausers on a floating line. Use a typical upstream cast and mend drift with the dries and let the fly tail out sometimes and drag a wake before you retrieve. With the wets on the dry line use the downstream swing and twitch, alternate retrieves and speed.
There are still some very nice dollies there too I caught several to 5 lbs in Aug/Sept using black and/or purple Marabou Leeches, on a sink-tip. This time of year you might try flesh type or Egg Yarn Flies on a sink-tip.
Not sure of the water conditions of late but should be OK higher up. Good spot about 6 miles heading east of Oso turn left on C-Post road ( 1 mile and park at bridge) or go another 1.5 miles up straight away for another good area on left (you will see it). Fish the seams along riffles running near boulders and other structure.
Nice thing there is you never know when a Summer run (keep up to two hatchery) is going to come up an nail your fly.
Good Luck
KRM
O.K. Now can someone point me to an area where I can take some nice Coho on my fly rod? It collects way too much dust this time of year in the Post-Humpy/Pre-Chum North Sound doldrums. I can get em in the salt but for the life of me I cannot ever get consistent on Silvers in the river (hence my plug pullin, spinner castin, Spoon drifting, egg tossin ways this past month)