If you can avoid the magnetic pull of the Golden Gate Bridge and San Francisco, take the very 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 visitors 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 you can tour an intact but no longer functioning 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), which has dorm beds and private rooms for around $20 per person.