If you could, I would change your flight to go into Oakland. The drive is a bit shorter to Napa from there...
You might also want to call some of the wineries before you go, as some places get busy and can only be seen by appointment.
I would highly recommend
Kuleto. Beautiful place, but you gotta call for an appointment for tasting. Excellent wines, especially their Chardonnay if you're lucky to get a tasting of it. It's a bit of a tricky drive to get there, but well worth it.
A very cool tour to take is through the
Del Dotto Cave. You get to taste straight from the barrel, pretty good wines (the Cave Blend I believe is their most popular).
Something else that is a bit different is
Round Pond. It's a winery, but also across the street is their olive mill where you can taste their olive oils. Again you might need to call, but excellent if you're into different olive oils.
Someone already mentioned V.Sattui, which is nice. And the ride up the Sterling cable car is great, but their wines are just ok. Across the way from that is a winery that has a sort of castle looking thing that I've wanted to check out, thought I don't know the name of it.
There are so many just on the 29, you won't have any trouble finding a variety of places to go. Talk to the people who are pouring at any of the tasting rooms for their other favorite winery, you never know what kind of jewel they have hidden up their sleeve.