Yes. Just tell them you'd like to take the Castle Tour; they'll point you in the direction you need to go. It's a self-guided walk-through at your own pace. You'll exit through the "chicken exit" just before the loading area.
Alternatively, if you have a 2nd adult in your party who can wait with your son, they do offer child-swap. You could all go through the regular que together. There's a nice room near the loading area where your son and an adult can watch Harry Potter movies while you ride. Then, once you're off, you can wait with your son while the other adult rides without having to go through the que again.