The kids didn't enjoy it as much because all they wanted to do was get in the water. The park rangers threatened to kick us out of the park several times when the kids got down into the stream.
We did Stony Brook the following day. It's nothing like Watkins Glenn, but the kids probably enjoyed it more. There is a trail next to the river, but everyone who hikes up the canyon there basically does it in the stream and ignores the improved path.