The problem with most west side rivers in the fall is rainfall....rivers could be in prime shape and within hours be blown out! I guide primarily east of the cascades on most Columbia river tributaries. The Klickitat opens June 1st and you can always find me floating it on the opener but flows run at around 3500-4000 cfs, its glacier feed so clarity from Aug-Sept depends on summer temps but by October temps drop, flows avrg 700-1000 cfs, salmon are also in the system and spawning so its game on!!
The Methow is a great fall river it runs crystal clear, flows avg 600 cfs and the black top follows the river so access is fairly easy. It is more of a typical trout system filled with riffles, runs, pocket water....steelhead can be had on the swing or "DRY" and on a size 12 bead head nymph! Best thing is it lacks the westside crowds