Here's a tip for anyone who loves wine, and wine tasting: forget Napa (and all that traffic) and go instead to Paso Robles California, home to a smaller number of really excellent wineries.
Paso Robles is blessed with the longest grape growing season in the US, and perhaps in the world. Generally cool at night, some locations are not affected by the coastal fog and others are: Mini-climates allow for vineyards, some on the same road, to have differing styles of grapes and growing seasons.
We are lucky enough to live within two hour's drive (at speed) of the place, but it's worlds away from the coastal fogginess of Monterey, where we live.
Some new developments include the introduction of numerous Syrah and Zinfandel Port wine makers to the valley, introduction of the table grape used for the making of port, the Black Manukka, and a growing olive oil business.
For safety's sake when tasting there are numerous vans and limos to take you from place to place. We've used the Wine Wrangler, a company that I'd highly recommend.
There is a nice Courtyard in Paso Robles, and another a half hour south in San Luis Opisbo. Both nice, friendly staf, but weekends are very pricey--recently Paso Robles was charging the rack rate of $239 a night!
Hey Stepping Stones
A great place to stay along the Central Coast with great service and super staff is the Santa Ynez Valley Marriott just off Highway 101 at the Solvang/Buellton exit. Wednesday evenings at 5 PM, there's a fun manager's reception in the lobby by invitation to Golds, Plats and Premiers and featuring a different local wine each week. Besides, GM Mike is an excellent host.
Try it when you are in the area!