Lawrence, here is a list of my favorites and where I purchase my wines. All but two are in Sonoma. My purchases of Napa wines is rare these days. Will give a brief description of each and where they are located. In no particular order. You can bunch several of these together based on location and make a leisurely day of tasting.
Bedrock: Big variety, zins, syrah, whites, blends. Tasting room in the town of Sonoma
Ceritas: Chardonnay, Pinot Noir and one cab. Location in Healdsburg. Appointment necessary
Dirty and Rowdy: Mourvedre, chenin Blanc, white and red blends. I think Hardy takes visitors by appointment. Location Kenwood
Idlewild: Piedmont Varietals grown in Mendocino. Arneis, cortese, dolcetto, barbera, nebbiolo, red and white blends. Tasting room in Healdsburg
Calluna: Cabernet and Bordeaux varietals, blends. Location Windsor. Appointment necessary.
Jolie Laide: Eclectic variety of wines, Melon, Gamay, Grenache, Syrah, Trousseau Gris etc. Not sure if Scott sees visitors, call for an appointment. Location, Barlow in Sebastopol
Ryme: Eclectic variety of wines. Two different vermentino, cab franc, alianico etc. Appointment necessary. Location Forestville
Scherrer: Big variety, Cabernet, zin, pinot noir, syrah etc. Appointment necessary. Location Forestville
Leo Steen: Three different Chenin Blanc, grenache, syrah, chardonnay. Tasting room in Healdsburg
Ruth Lewandowski: if you want to try “Natural Wines” sans soufre. White and red blends, sangiovese, merlot. Tasting Room in Healdsburg above the Idlewild Tasting Room. Appointment necessary.
In Napa I have a couple whose wines we enjoy.
Frogs Leap: Variety of wines, Cabernet, Zin, merlot, chenin blanc etc. Location in St Helena. Appointment necessary.
Matthiasson: Variety of wines, red and white. Location in Napa. Appointment necessary
We live out here so if you need other recommendations for food, lodging, sights to see, things to do other than wine, just ask or shoot me a PM.