Read up on the location:
www.concierge.com
travel.nytimes.com
sfgate.com

From San Francisco:
Allow 2 hours
Take Highway 101 North to Santa Rosa North of Santa Rosa
Take the River Road/Mark West Springs Exit
Immediately turn right onto Mark West Springs and continue for 10 miles
At stop sign, turn Left onto Petrified Forest Road and follow for 5 miles
At Highway 128, turn Right, follow for one mile
At flashing red light and sign for Calistoga, turn left onto Lincoln Avenue

From Oakland:
Allow 2 hours
Take Highway 80 toward Sacramento to Vallejo
Take Highway 37, the Napa exit. It curves over Highway 80 to the left, follow for 1 mile
Turn right onto Highway 29 and follow north for 40 miles to Calistoga
At flashing red light and sign for Calistoga, turn right onto Lincoln Avenue

From Sacramento:
Allow 2 hours
Take Highway 80 West toward San Francisco
Exit Highway 12 to Napa, follow for 5 miles
Turn right onto Highway 29 and follow north for 30 miles
At flashing red light and sign for Calistoga, turn right onto Lincoln Avenue

Map from calistogavisitors.com

Transportation:
Valley Valet Taxi: (707) 942-9009
Calistoga Limousine: (800) 617-0180
Yellow Cab of Napa: (707) 226-3731
Wine Tours Transpo: http://www.californiawinetours.com/index.html