I suggest Marin or Santa Cruz Counties in particular, though Sonoma is good too. You just need piles of money, and a vehicle with a good sturdy suspension because the roads are no longer maintained as California devolves into a failed state.
We had a three-way tie for valedictorian of my 20-person 8th grade class at West Marin Elementary of Point Reyes Station in 1963 - me, Jay Power (eldest son of the chief Ranger at Samuel P. Taylor State Park) and Hattie Rubenstein (step-daughter of science-fiction writer Phillip K. Dick). Hattie drew the short straw. We next saw each other as freshman at the brand-new UC Santa Cruz campus in 1967. All three of us wanted a small elite college on the coast set in a redwood forest, similar to what we had grown up in.
It does get cold on the Point Reyes Peninsula in winter though. Plus in spring there are white caps in the stock tanks and you can wind-surf in the stock ponds.
You really will need piles of money. But it's gorgeous.
BTW, if you know much about Phil Dick, consider the effects on a young boy of having him as THE adult male role model during adolescence. And reading his entire library.
I’m CA born and raised, mostly in the rural areas of Sonoma County but we also lived in San Ramon in the east bay area. When I first lived on my own, it was in a Concord apartment. I left at 19 when I joined the military, and ended up living in MD (after a wonderful tour in Europe). I came back to CA when I went to graduate school (PhD, UC Davis) and then ended up moving back to MD. I stay in Windsor whenever I come out to visit family.
I do miss CA, but it has changed in some very negative ways since my childhood. The cost of living out there is quite high, and it seems the infrastructure and some areas are crumbling. MD also has a high cost of living, but we live in a nice area just outside of town.
I’m considering TX when I retire. It is not nearly as expensive.