Most National Parks, State Parks & Wilderness Areas require a backcountry permit registration previous to getting on the trails if your planning for an over night visit. The purpose of this is to locate backpackers of an emergency (wildfires or storm dangers). Free permits can be obtained free at most visitor centers or ranger stations. Many parks have trail head parking spots with self-registration.
Access roads to the Wilderness trailheads are sometimes dirt & may be ungraded, very long & very remote. Pick your trailhead depended on the road conditions, grading & snowfall amounts. Call a field ranger for more up-to-date info. And know your cars limitations. Mud or creek crossings are quite common. Plus the Waterproof maps by Tom Harrison are the best choices for backpacking.
Below are the pages to all parks & forests in California, some lakes, plenty trailheads, plus the high Sierra bliss.