We have over a hundred sizable parks in a short distance - NP holdings (Pt Reyes, GGNRA), several large State Parks, many many Regional Parks and Open Spaces, some quite large too. I can only think of three or maybe four of them where crime is an issue - mostly smash-n-grab thefts of things unwisely left inside cars at conspicuous tourist "must-see" parking lots. I've parked at some of the same places hundreds of times without incident; but I drive an old truck without any hint of something of value inside. Yeah, there are a handful of movie-worthy exceptions from the wacky 70's of some psycho roaming around the woods - Zodiac and the Trailside Killer - but you've got about a 100,000% more likelihood of being assaulted in your own local shopping center. And muggers are a lot more interested in stealing a pair of cool tennis shoes than a pair of bird watching binoculars. Trails aren't their thing. What I worry more about are the little felons - ticks in season, nettles, poison oak, etc - all easily circumvented with a little common sense. Demographically, after decades of experience, it's on the trails that you seem to meet the nicest and least worrisome people, out to enjoy things themselves. Over the years a few rude jerks inevitably turn up, but that's the exception. Even critters are rarely a worry the further back you get; even black bears avoid human encounters unless they've been habituated by a junk food habit. I've had em feeding on berries all around me at night without them bothering me or my gear. ... but mice ....