With stunning views over an area 40 percent larger than Golden Gate Park, the Presidio is sometimes overlooked for outdoor adventures. An army base from 1776 (by the Spaniards, the same year as the Mission Dolores) to 1994, and now operated by the National Park Service, the area is not especially developed for recreation, but provides it nonetheless.
Deer, wild flowers, goat trails, a golf course, a bowling alley, a small lake, a variety of old military buildings (now residential rentals), the Lucasfilm studio, the Walt Disney Family Museum and others share the Presidio.
Adjoining Crissy Field, the Marina, the Golden Gate Bridge, Baker Beach, Seacliff and the Inner Richmond, the Presidio is readily accessible from the north side of San Francisco - all with short (if steep) biking distance.
Website: http://www.nps.gov/prsf/
Wikipedia: http://en.wikipedia.org/wiki/Presidio_of_San_Francisco