Napa Valley
The towns of Sonoma and Napa are surprising close, separated by a distance of 15 miles over low rolling hills. Once you’re in Napa, you can drive-up the west side of the valley on Hwy 29, or drive-up the east side on the Silverado Trail. At the top of Valley, in Calistoga, you can reverse directions.
Link: Napa Valley Visitors Bureau
Driving Directions from Sonoma, past the Town of Napa, up to the top of Napa Valley (town of Calistoga)