Hi, David! Thanks so much for the compliment about the site! We love to hear people are enjoying visiting us!
Disney Mom Tanya and I are not known for packing light, but I think if I was traveling with just my husband and one daughter instead of the three I usually travel with, I'd probably bring a small backpack with my camera - which I take everywhere; sunscreen; hats, visors, or sunglasses; and then things like your room keys, identification, credit cards, etc.
Other things you may want to take include some light snacks to tide you over - raisins, crackers, juice boxes, and things like that. If your son is still interested in the characters, you could also bring an autograph book and pen.
Whew! Even when I'm not thinking of over packing, it sounds like a lot of stuff to bring!
Have a wonderful vacation!