On your way north you will go through the toll booth area at the Golden Gate Bridge without stopping. There is no toll in the northbound direction. Admire the beautiful view as you drive over the bridge. To your left are the Marin Headlands and the Pacific Ocean, and to your right San Francisco, Tiburon, Angel Island and the San Francisco Bay.
When you near the end of the bridge, you will have an opportunity to stop at Vista Point, which is a fantastic setting to admire San Francisco Bay, the Bridge, and the San Francisco skyline. If you are up for a walk, you can park your car and walk along the pedestrian sidewalk on the west side of the bridge. If you happen to arrive on a weekend or holiday, be aware that the backup to the parking area at Vista Point can be substantial, so plan accordingly.
As you continue on Highway 101 north toward Santa Rosa you will have several options for a short sightseeing excursion in Marin County: you can, for example, exit in a few miles and visit the town of Sausalito, with its many shops and beautiful setting on San Francisco Bay. Further along, you can make a scenic detour to spectacular Muir Woods, but this will add several hours to your trip.
Unless you are planning to spend the night in the wine country, we would not suggest that you try to stop at Muir Woods if you also want to visit Napa for just the day. While this trip is possible, you will probably regret not having enough time to take the necessary time to enjoy both destinations.