Im going up north the middle of the month and have already booked appointments with Carlisle and Walter Hansel but am looking to add one more. Looking for something boutique preferably and definitely more Old World oriented. Off the beaten path is always a plus too. Thanks in advance! 
Benovia-nice pinots and chardonnays and zinfandels. Small place, just built a new tasting area
Copain fits the wine description best, plus it’s a beautiful location. Requires an appointment, and they have a modest tasting charge, but it’s worth it. Boheme out in Occidental is another rec.
Jolie Laide
Bump Cellars has an art gallery with ever-changing exhibits. The wines are killer, but the reds (the Zin/mixed blacks - what I tasted) are promising long-term agers. The “Fortuna” white blend is very yummy, too!
I am certain that any other wineries I could think of will be mentioned…
Calluna. Chalk Hill area.