I typed in "Folsom knitters" in google and got this page. Apparently there are some knitters up there. Not sure how you'd proceed from there.
There was a member here from Folsom "RacerKatie", but she hasn't posted in a long time. Hard to tell who else might be up there since most people just put generic locations. Hope you find someone!
ETA...also try yarn stores, they usually have a knit night.