We go every year. I camped up there in June with 19 kids under 5, and, 20 adults who all wanted to catch fish.
We rented the pontoon boat for the day, and did shifts of 8 ppl at a time, and everyone caught fish. I was on the water from 7 am to 7 pm.
We used light line and a small bobbers with a small white crappie jig about 18" down, catching all the crappie you could want. Even 15 lb line on the Dora fishing rod was getting bit. The Heron Point area was good and had lots of herons to watch, too.
Helpful page from the helpful rangers -
http://lakecuyamaca.org/how_to.htm#F...SER%20MINIJIGS
With the kids, trout this time of year can be tough until after about Labor Day. Hope that helps.