You need a plan and flexibility to really enjoy Clementon Park. A few years back my daughter was in AM pre-school and my son was 7-9 months old. I was at home for the summer. The season pass is reasonably priced at $49.99 a person and includes free bring a friend passes. We got a lot of enjoyment from the park that summer by going on May/June afternoons before school got out and late summer afternoons around 4pm.
Weekends are not really an option. It is a zoo. You can ride about 4-5 rides in the time we did the entire park at non-peak times. While that is true of other amusement parks as well, summer days can be overrun by local kids without proper adult supervision - especially at the water park portion.
There is a small section of rides for kids 36 inches-48 inches. Shorter than 36 inches and you are limited to the train, the carousel, and one child ride that you can ride with an adult. We had a blast the summer my daughter was 4 and just over 44 inches. She was able to ride all of the little kids rides AND most of the big kids rides, including a bunch of the bigger waterslides.
The waterpark has 2 areas good for younger kids - the newer castle play area with several slides and water play is in extremely shallow water and great. It's consistent with what you find at sesame place and well-know indoor water parks. The child's pool area - about 1 ft deep with a cute pirate ship unfortunately usually stinks of pee.
Younger impatient kids would really enjoy the park during non-peak times. Older kids that can be trusted with a pack of friends would have a blast - but this isn't really a once a year day-trip kind of park. You really get your money's worth by getting a season pass and going for many short periods of time.
I would recommend it for South Jersey locals.
Clementon park is a small park in south jersey. They have a water park, as well as a dry park. You can purchase a combined park ticket or choose which one. If you live in south jersey, this is a small park with some good rides that you don't have to pay too much or drive too far for.