You and your son are going to have a blast at
Walt Disney World! It is a fantastic place to create some great memories. As for the backpack; I got you covered. To begin with you will need the other layer of clothing, the sweatshirt, hat, jacket, maybe even a little blanket if you have the space. Make sure to bring snacks like crackers, fruit, granola or whatever foods you both might want. Water bottles are usually a good item, although they can weigh down the backpack. Those are the essentials. From there everything else is optional. My kids loved getting autographs at the
Character Greetings, so I carried those for them, as well as their pins, lanyards and everything else we parents must carry. Some parents bring another layer of clothing, it just depends on what you think you will want. I think you and your son are going to have such a great vacation now that the whole backpack issue has been resolved! Have a magical trip and take lots of pictures.