There are so many, it kind of comes down to "visit the places where they make wines you like."
And avoid weekends if you can, because of the traffic.
I always like to start a trip at Hess Winery, though. The wine is good, but more important, the winery is a beauty, with a self-guided winery tour wrapped around a modern art museum of real quality. It's up Mount Veeder from the city of Napa, giving you a scenic drive away from the mob on the valley floor, but it's not that long a trip, maybe 15 minutes from the town.
https://www.hesscollection.com/Clos Pegase also has good wine, a spectacular winery designed by Michael Graves, and a public art collection, and it's right in the valley in the Calistoga region.
https://www.clospegase.com/