"Join SF Bicycle Coalition member Tim Hurley on a family ride traversing Marina Green and Chrissy Field, then through the Presidio to the Golden Gate Bridge. Once across the Bridge, it's a curving coast down to Ft. Baker. The return trip follows the same course, so those who wish to visit the Discovery Museum can separate from the group and return on their own. Walking bikes up the hills is encouraged! Due to distance and hills, this ride is recommended for kids on 16" bikes and above, and not recommended for training wheels."