We found the gravel lot past a few trailer homes but it was blocked off with a gravel built up barrier. Could have parked parallel in front of it but felt weird about it. We went back a little bit to a turn out before the homes, across from a huge open lot to a one van turn out with large boulders . It was quiet and a peaceful spot just minutes from Humbolt State Park—Founders trailhead loop.
Somewhat sketchy and trashy. Had some people come by at 3am to steal gravel. Pit worker showed up at 7:30am on a Saturday but didn’t bother me. Place is fine in a pinch.