At the time of this writing campfires are not allowed due to fire restrictions. Alcohol is also not allowed in the Piru Recreation area. Depending on your camping style this may be a deterent.
However Lake Piru is close to Los Angeles and near the Magic Mountain amusement park and probably more fun than staying in a hotel. During my stay at Lake Piru I even saw deer grazing in the grass. See below for more information on Lake Piru.