Re: Fly fishing spots in Napa/Sonoma area?
I might suggest taking Hwy 128 from Calistoga through the Alexander Valley to the Russian River. I think if you do a quick www search you might find plenty of information about guides for that fishery.
P.S. (on edit) The advantage of Hwy 128 is that if the fishing is poor there are several dynamite wineries along the way.
Snake River Plain