Providing stunning city views, spooky military ruins (which you're "not supposed to" explore), fishing, and one of the better frisbee/picnicking fields you'll find - Cavallo Point delights.
And drinking! Farley Bar, situated on the edge of the main green, provides a great deck with couches (and blankets) for enjoying drinks, appetizers, and dinner. Inside, two fireplaces spell "sun" on the rare occasion Marin doesn't.
Address: 601 Murray Circle, Sausalito, CA
Website: http://www.cavallopoint.com/