If you can avoid the magnetic pull of the Golden Gate Bridge and San Francisco, take the last turnoff from US-101 (northbound drivers take the second turnoff after crossing the bridge) and head west to the Marin Headlands, a former military base that’s been turned back into coastal semi-wilderness. A tortuous road twists along the face of 300-foot cliffs, giving incredible views of the bridge and the city behind it. The road continues west and north to the Visitor Center (415/331-1540), housed in an old chapel, with a reconstructed Miwok shelter and details on hiking and biking routes. And if you’re so inclined, on Wednesday-Friday afternoons and the first Saturday of each month, you can tour a restored Cold War-era Nike missile silo (free).
Nearby, the barracks of old Fort Barry have been converted into the very peaceful HI Marin Headlands Hostel (415/331-2777, dorm beds $31 and up, private rooms $105 and up), which has dorm beds as well as private rooms.