If your trip destination is the northern California redwood forest and you are starting at San Francisco, you will probably take highway 101.
This location is part of my "Redwood Parks at Northern California Coastline" road-trip suggestions and trip planner blog.
You can also
have a much longer trip if you want to travel north on highway 1, see many other
blog posts I have on Point Reyes, Bodega Bay and Mendocino at:
My main highway 1 trip planner blog: