I have a few friends in Santa Cruz, which is fairly close, that train. They're not on here, but they are on
SFPK, and you might find people on PK Cali like Alex said.
There are large active communities in Southern California, Sacramento and the greater Bay Area. The more rural or isolated areas of California are a bit more hit and miss as far as finding people. Often there's one or two people and if they're young, like most traceurs, the community dies when they go away to college or seek a career elsewhere. If there's nothing going in Monterrey, you can always start it up! Also, SFPK has a rotating monthly jam where we all meet up in a different spot each month. We've gone as far north as Santa Rosa (where I am), as south as Santa Cruz, as east as the Sierras and everywhere in between. If you can only make one big drive for PK a month, this is a great way to be part of a larger community.
Also, several of us from all the different communities in California are trying to communicate more and establish some cool things for the future of parkour in California... so it's a great time to be coming to live here! Hope to see you at a jam!