Ahh my backyard. Honestly you can't go wrong anywhere in the valley. Hopefully the weather holds up today as well as it did yesterday, I haven't been in a few weeks, but if the grape leaves have all not fallen off you're in for a treat. There is probably a better chance for that on the north end of the valley (st Helena and further up) than on the south. As neuro stated domaine carneros is pretty, but if the weather is really clear (no marine layer) then skip that and try artesa instead (maybe 3 mins from domaine carneros) the wine is S___, but from their balcony on a clear day you can see all the way to the golden gate. Then I'd hop over to Nicholson ranch, their wine is better than the two above plus Charles the tasting room manager is a riot. If they'll let you walk around the grounds there is a quaint little chapel up on the hill built by the owners father a long time ago and a huge lion statue used in the sf opera. From there it will probably be getting close to lunchtime. Then there are a couple of choices, if your going to Sonoma, Sonoma town square is very picturesque and most of the restaurants on the square are good and reasonably priced. If your headed up the napa valley then for cheap lunch I'd recommend stopping at oxbow market, lots of choices there including gotts (formerly taylors refresher) or head up to oakville grocery for good sandwiches. For the higher end of lunch head to yountville. Personally I love buchon, Bottega, or ad hoc (they only offer lunch take out). From there the world is your oyster...I'd recommend the following for wine tasting, caymus, hall, Robert Craig, patz and hall, schramsberg, Joseph phelps, honig, duckhorn, pine ridge, chimney rock, page. For sight seeing more so than wine drinking, Coppola, mondavi, beringer, sterling. I am sure I can come up with a lot more. Let me know what kind of vino you're in to and I could provide some more specific recommendations.