Relatively small pot farms have been discovered in Castle Rock State Park in the Bay Area between Palo Alto and Santa Cruz: "Drug-gang farmers increasingly squat on state lands". The drug gangs are from Mexico, and the tenders of the plots are illegal aliens from that country, some of whom are apparently armed:

...One plot was found after a mountain biker stuck a note in a ranger’s kiosk at Nisene Marks State Park, and another was spotted by a fisherman near Skyline Boulevard, he said. That man was confronted by armed men believed to work for a Mexican drug cartel, he said.

But because the plots are remote, deputies get more complaints about the noisy helicopter than about the marijuana plantations...

...In the county, over the years, [Joanne Danielson, public safety superintendent for Santa Cruz district State Parks] said, gardens have been established in in Castle Rock, Big Basin, Henry Cowell and Nisene Marks state parks.

These are rural areas which are located not far from large estates inhabited by some people who are very rich. Perhaps they'll decide that living with helicopter noise is better than finding that cartels are growing pot on or near their property.

On a Bay Area visit a few years ago, I snagged some county highpoints, two of which are very near Castle Rock. Unfortunately, I didn't have time to visit that park as I understand there's some rock climbing and scrambling. This page describes a popular hike there, and this page describes the 32 mile Skyline to Sea trail. There's a good map here.