A 21-mile self-guided audio driving tour from Point Reyes National Seashore to the town of Tomales.

Just across the Golden Gate Bridge from San Francisco, fifth-generation sheep rancher Bill Jensen guides recalcitrant lambs through a foot bath. A few miles down the road, Bob Giacomini checks out his high-tech milking barn.

Bill and Bob are part of a rich agricultural community of dairy farmers, cattle and sheep ranchers and oyster growers in West Marin County. How was this rural paradise, so close to a major metropolitan area, saved from development? A lot of the credit goes to two women who came up with a unique idea...