Take the Ferry between Ferry Building downtown and Sausalito. In Sausaltio you have Le Garage, Sushi Ran, Heath Ceramics. In Ferry Building there are ton of great restaurants and artisanal food stalls (meats, cheeses, breads, coffee, etc)
Many people will say Union Square has the best shopping but, I disagree. I think Haight does- it has funky shops, fantastic restaurants and bars, Amoeba music, Ben and Jerry's, vintage clothing stores, and Golden Gate park is at the end of it.
A great place to rent paddle boats, kayaks or bikes to bike around the Park to see all of the different Golden Gate Park sites- deYoung, Palace of Fine Arts, the Bison roaming freely, Japanese Tea Garden....or you can pack a picnic and have a picnic after a day of rowing on the lake.