There is a state-park anti-nudity ordinance that has in the past been interpreted in court to apply to traditional clothing optional areas only after a complaint that day and a request to cover up.
There is a parking fee, and the lot frequently fills on sunny weekends. Clothing-required camping spots are available for an additional fee.
From I-5, take Basilone Road southwest to the state park. Use Trail 6 and walk south along the beach at least 100 feet south of the last life-guard tower before disrobing. Do not go beond the remains of the fence that separates the park from Camp Penelton.