I lived in the pope valley area till recently, and I fished upper putah off of snell valley road (a right turn off of butts canyon rd heading towards Middletown) a number of times. I only caught small size smallmouths but the area is a trip to explore, lots of snakes as you'd expect. Believe it's public land, but have been told conflicting things from the residents at that particular spot. Only other thing I have to add is that upper putah in hidden valley (parallel to Hartman Rd), had some very large fish stuck in a pool last April. I was working on a construction job there, and would watch them after work, but couldn't figure out species. They were sort of silver colored, but water was way too warm for steelhead, so maybe squawfish or carp. Again, I'm not sure about access as plenty of people swim under the bridge in the summer, but there are no trespassing signs along Hartmann rd.
Can't imagine anybody getting hung up about me talking about these spots, as they receive little to no pressure for good reason.