We've stayed in Santa Rosa at the Sonoma County Fairgrounds. It honors many camping discounts such as Passport America, Good Sam, Escapees, etc. They have full hookups and is very reasonable.
We then drove on 101 south to the north side of the bay near San Rafael and picked up the ferry at Larkspur Landing. It took us by Alcaltraz Island to the Ferry Building (shops/food) and we had pre-arranged for this small van tour to meet us there. It was an extremely good day of touring with a small group and we visited every top spot of the city. They drove across the Golden Gate for lunch in Sausalito. We were able to get out at each attraction and enjoyed a decent amount of time at the Japanese Garden. Our daughter who lives there was very impressed with the tour.
https://www.sanfranshuttletours.com/