The fried chicken and meatloaf are both hits with my dd. My son enjoys the fish sandwich and chicken pot pie (he's 15 and eats off the adult menu). I know my dd got a kids portion of the meatloaf off the kids menu, the fried chicken she and I just split and it was a perfect portion for the two of us.
Both my kids LOVE the peanut butter and jelly shakes.
I think your son will have fun. I know this is one of my son's favorite places to eat in all of WDW, when he was little and all about the characters, and now when he's big and all about the food. He also gets a huge kick out of the servers, the old style decor and tv's and just begs me to go each time.