On my last visit to Lake Casitas I stayed in Mallard 32 which provided a fantastic lake view and was near a Aircraft Runway used for Radio Controlled Aircraft. The Mallard or Osprey campgrounds are the furthest from the park entrance and have the most remote feel. If you are looking for a campsite closer to the boat ramp or park entrance I would choose Angler, Bass, or Creekside. During hotter months and especially in the summer you should try your best to find a shady spot. Not all campsites provide enough shade.
The park also has a small waterpark and hosts several events throughout the year. The event that I enjoy the most is the Ojai Wine Festival. It usually happens in June. For more information visit www.casitaswater.org/department.php?url=lake-casitas-recreation-area.