Great Adventure has a good amount of kids rides scattered throughout the park. Our youngest is 6 so while she can go on some of the 48″ roller coasters like Skull Mountain she can’t go on the bigger ones yet. While my older daughter and I go on Nitro she will head to the kids area nearby.
The area right outside Nitro, next to Seaport Eats, is called Safari kids. This area has 3 rides, though one was shut down today.
The biggest ride in this area is Safari Tours, a tracked car ride. It drives around a little landscaped area with animal pictures and statues.

On the other side of the fountain is a slow spinning balloon ride called Sky Zooma.
Finally there is Jumpin Joey, a bouncy tower lift ride. Last time we were here the seat was totally removed from the track. This time it’s back on the track but still closed, so I guess that’s progress!