I agree with the above post. Mendo, Humboldt, and Trinity have changed in the recent years. While to culture still supports it, the law enforcement is just way to crooked up there. Also, the gangs, and thieves have been running rampant. You could have a plot of land miles away from even a paved road, and still get ripped off. I lived in Mendo, and while the culture is still 420friendly, the cops are not.

The climate up there isn't quite as perfect as it's made out to be. Powerful storms blow in nearly every October and can really cause problems. Also, the fog near the coast isn't the best thing for outdoor plants. Fortunately, the cold climate of the coast makes it loads simpler to grow indoors all year, and not have to worry about excess heat.

It's been mentioned that Sonoma is a good place. While the culture isn't nearly as open as Mendo/Humboldt/Trinity, the climate is what I would consider ideal. Cool nights(generally around 50), warm afternoons(around 75-90), and far enough south that some of the early storms either don't affect Sonoma, or don't hit with nearly the intensity. One thing that you have to consider is that Sonoma is quite expensive, and extremely private land is a premium and difficult to comeby..... nearly impossible on a budget, since nearly everyone in Sonoma County does a credit check.

Lake County is another option. It's a little on the hot side, and water is a little harder to comeby, but land is cheap, and plentiful. The climate is also dryer than most other places in Nor Cal. Summertime can be around 85-95...sometimes more like 110. Usually around 65 at night. The culture is generally accepting of it too. And there aren't many people.

All this being said, it really just depends on what you want. Each area has a little different views on cannabis, and the cultures surrounding it are all different.