That is correct: no camping at the trailhead parking lot.
Want to disperse camp? go to East Flats camp area (East of South Fork trail on Jenks Lake Road about 1/4 mile before you get to Highway 38 on the Jenks Lake Rd East entrance.
California fire permit required if you plan to use a camp stove at East Flats – No Open fire allowed. Get a free fire permit at the website:
Hope that helps