Be warned, there are no rental car companies within the city of Sausalito. If you don't plan on renting a car from the airport and would like to have a car for the day, be sure to check with your hotels concierge.
If you will be visiting Sausalito for a short time, most people choose to explore Sausalito by bicycle. Besides cruising along the shops and restaurants along the waterfront you can ride over to the beautiful Marin Headlands and even over the Golden Gate Bridge. In fact, many people who want to visit Sausalito will actually bike across the Bridge from San Francisco, spend time going through the many shops, museums, and art galleries, and then head back home on bike or by ferry.
Of course, if you plan on getting up to the wine country or our beautiful coastal beaches, be sure to arrange for transportation in advance!