Mount McPherson (also known as Mount Bielawski*) is located on an closed-down Christmas Tree Farm right off Skyline Boulevard in the Santa Cruz Mountains. It is the highest point in Santa Cruz County. It is very close to Castle Rock State Park which offers some rock climbing opportunities. The Christmas Tree Farm used to be only open, obviously, during the weeks leading up the Christmas, but has since been apparently abandoned. It is not clear as to whether or not an ascent of this peak is legal nowadays, but it is still best to keep a low profile while bagging this one. Luckily it is located right off the road, so it shouldn't be too hard to sneak up to the summit.
*Mount McPherson appears to be the name of the name of the "massif" this highpoint is located on. Mount Bielawski appears to be the name of the "summit" where a firetower is located, less than .2 miles west of the highpoint.
From Los Gatos, get on Highway 9 south and stay on it until it reaches Skyline Boulevard. Turn left on Skyline and follow it for about 3 miles until you reach a nondescribt dirt road on the right with a couple mailboxes. Take this dirt road, stay left at the fork, and you will end up in an abondoned Christmas Treet Farm. The highpoint is located at the bottom of some fir trees on the eastern edge of the farm.
The summit is on private property, but whether or not it is frequently patroled is unclear. Clandestine hikes appear to be do-able, just be sure to keep a low profile.