We did the Segway tour last November and enjoyed it so much, we're doing it again next week! You spend about 45-60 minutes learning how to ride the Segways, turn corners, go up and down ramps, etc., and then head out in the World Showcase and have a guided tour through the countries before they're open.
Its a lot of fun and we were surprised how easy it was to learn. Within ten minutes or so, it became second nature. I think your son would love it.