Hi - We are doing a couples trip to Napa and flying into San Francisco. One couples flight was changed and now we have 4 hours to hang out in San Francisco until we need to go back to the airport and pick them up with our rental car. What are some things we can do to enjoy San Francisco in that short amount of time on a Tuesday? We arrive around 10am. Once they arrive we will pick them up and drive to Napa Valley.
Thanks in advance for all of your help and suggestions.