I own a dark-sky (well, darker sky) observing site in the hills northeast of Pinnacles National Monument, southeast of Hollister. It is forty fenced acres of grassland at the 3000 foot level (tops) of the Diablo Range, just west of Panoche Pass.
Before I bought this site I looked at, and observed from, many hilltop locations south of San Jose. You can read about that at my page about looking for a site.
My site is dark for a location within two hours of San Jose. The ClearDarkSky map shows the location to be "in the blue", but it isn't really that dark. (The CDS light pollution data is not current.) The horizons are visibly light-polluted in most directions: Hollister and Salinas to the north and west and the Central Valley towns from Merced to Fresno in the east. Normal zenith SQM readings at the site vary from 21.3 to 21.6. The gegenschein can be seen when it is in a favorable location.
The location is good for visual observing because there are no nearby light sources visible -- no porch-lights, no car lights. The southern horizon is excellent for reaching southern targets like omega Centauri and the Vela SNR.
The site is primitive with no "modern conveniences". I have the two shipping containers for storage and a picnic table; there is no power or plumbing. There are minor amenities, like a generator and tools and soap and water and chairs and a car-camp potty, in one of the containers.
The last 2 1/2 miles of road is uphill dirt but it is drivable by an ordinary vehicle as long as it is dry.
You can look at the site (and see the containers) via GoogleEarth at 36 40 24.7 N 121 01 29.3 W. Most of this GoogleEarth image is my forty acres of grasslands: the north, east, and south borders are visible because the property is fenced. (The west border is barely visible at GoogleEarth and difficult to see here; at the southwest the fencing follows the road and does not include the property's southwest corner.)
I use the flat area at the containers and the ridge above the containers for observing, the latter can be windy. There is room for about five cars-worth of observers at each spot.
I currently observe from the site several nights per month, usually at new moon. I have several telescopes at the site, including a "bent" six-inch refractor RFT and a bent eight-inch refractor RFT (with a flip-mirror to a four-inch) that I have been using with nebula filters for the past few years.
If you would like to observe from the site, contact me via the information at the homepage