If you're headed to wine country for some sipping and spinning, I'd encourage you to start and finish your day at the Clif Family Wine tasting room and their all-bicycles-welcome back porch at Velo Vino in St. Helena. It's the perfect place to have your pre-ride coffee, fill up your water bottles, and hit the restroom before departing on any sort of mileage day you're looking to have among the vines.
If you're still new to exploring the bike paths of the area, be sure to grab Velo Vino's easy to use map, with different classic route options described at length. The majority of the "wine domestiques" on staff are cyclists themselves and they're more than happy to point out their favorite stretches of pavement.
Upon your return, be sure to sample the Clif family wines and Kit's organic nibbles and wander around the shop to check out the cycling-inspired artwork and apparel. You'll have worked up an appetite by then, and the Velo Vino back porch area is the perfect place to bring back a gourmet Gott's Roadside burger or Sunshine Grocer sandwich to enjoy with your wine.
Finally, a friendly tasting room in the Napa Valley that celebrates cycling, community, coffee AND wine. All things that Gary Erickson (founder of Clif Bar & Company) and wife Kit Crawford have long encouraged.
Andiamo and allez, get you and your bicycle to Velo Vino.