Here is the route we took from Menlo Park, south of San Francisco, to Redding, California. We took a zig-raggedy route through some beautiful areas of California, generally heading north because we knew we had to be in Portland on April 18 to meet my parents. I planned the route to generally avoid what I thought might be dangerous narrow steep roads, and we were mostly successful at that. The route from Santa Rosa to Petaluma turned out to be such a narrow, steep, dangerous road, and we had a person in a pickup pull over and offer us a lift, so we took it. Also, Highway 12 between Napa and Fairfield was quite a busy and fast freeway, and not exactly fun, but it did have nice scenery and a giant shoulder so it was okay. The Silverado Trail looks like a great route, but it is a really busy highway, although it does have a nice shoulder.
Highlights on this route included great camping at China Camp, Napa Bothe, and Solano County Park, some incredible quiet roads (especially Pleasants Valley and north of Oroville), lots of wineries, pretty mountains in Napa Valley, the Schulz Museum, and the Jelly Belly Factory. We never did really see much of the Sierra Mountains.
The red points with no dots in them represent where we stayed each night and the green points with no dots represent some of the sites we saw.