After crossing the GG Bridge, look for a road to the west. There is one that puts you on a hill overlooking the bridge and the city, great perspective for afternoon and evening. There is also a lighthouse and roads into Mount Tamalpais SP which has good scenery. Muir Woods is a good stop for redwood forests, but there are even more up the coast closer to OR. Point Reyes is worth your time.
I would stay on Highway 1 as much as possible for views of the coast. If it becomes foggy or just too slow, move out to 101 for better speed. You can take 101 on the return to see Sonoma wine country and several missions/churches (eg, Petaluma). Eventually, you have to take 101 which goes through the redwood country and on to Bandon. Great coast line and incredible sunsets along the way. Several great lighthouses along the OR coast, and places where seals can be seen, too.
I took this trip (all the way to Seattle) in a rental car in 1990. Motels were uneven in quality (I quickly learned to check before paying) and rarely where I wanted them. If I did it today by myself, I would camp instead, probably renting a big SUV and sleep in it. There are numerous state parks in both states, as well as other places to park for the night.
This should be a great trip and I'd love to do it again. I have been back on the OR coast in a motor home, but have not driven northern CA since 1990.