I'm heading out to Sonoma for a day next month and have booked appointments at Lancaster Estate and Chalk Hill. We will then head up to the Dry Creek area and hit Ridge, Zicicchi (sp?), Mauritson, Bella, and the Papapietro Perry tasting room. We'll grab a sandwich at Oakville Grocery in Healdsburg for lunch and probably do dinner in Healdsburg as well. After dinner, I plan on heading down to Santa Rosa to visit Russian River Brewing Company for some damn good beers.
Our napa portion of the trip is a lot of very small wineries that aren't open to the public but we do plan on walking in to Cliff Lede, Juicebox (they might require appt, not sure), BV, Chapellett, and we have appointments all up and down Spring Mountain where every winery is pretty good and the views are spectacular. As others have mentioned, Frank Family is good, and Larkmead, which is across the street, is just as good. Chandon is fun as well and they may be open later than the others for a night cap. Others we've enjoyed in the past are Grigch Hill, Del Dotto (appt required), Flora Springs, Spotswoode, Girard (might be open til 8:00pm still), Groth, ZD, Rombauer, Round Pound, and Tamber Bay...just to name a few.
Dinners in napa will be at Press, Bouchon, Ad Hoc, and either Brix or Mustards. Lunches include Cindy's Backstreet Kitchen, Cook, Rutherford Grill and maybe some In and Out.