I've not been to that part of California as I resided in the L. A. Toilet.
Is there a 2 or 4 lane road to access the now defunct Hamburger joint?
Is there enough space for Truck parking?
Is there access across or through a Fence from the Rest Area?
Maybe Porky Bobs was using other forms of Meat.
Maybe Porky Bobs was selling other than Food.
Maybe it was a bad Business venture considering Location.
The County Office should have clarification as to the reason(s) it closed or was closed.
Good Luck!!