When you're in West Portal and the adjacent Forest Hill and St. Francis Wood, it's hard to believe you're still in San Francisco. These quiet and picturesque neighborhoods are decidedly non-urban, yet they are connected by a streetcar tunnel that leads under Twin Peaks to the bustling downtown area, two miles through the city's mountainous core. In fact, West Portal is named for the western end of this tunnel, which opened in 1917 to bring residents...