I second the above post. My DS (6 1/2) LOVED making his own light saber in DHS. We had it delivered to the front of the park so we didn't have to carry it around all day and then picked it up before Fantasmic. We would have sent it back to the hotel, but DS didn't want to wait for an extra day.
I would also look into the "Jedi Tranining" show at DHS if your son isn't shy. They pick 10 or so kids out of the audience to participate and they get to fight Darth Vader at the end! Warning--if your DS doesn't get picked, you may have to attend shows all day. Many kids were disappointed when they weren't chosen. My DS DID get picked and it was the highlight of his trip--VERY fun and we have some great Photopass pics. from the show. There is a thread somewhere on the DIS with tips on getting picked.
Hope you have a great trip! I wish we could go back right now.