I ran the Disneyworld marathon in 2007. Its a great race to take your family too, because of all the peripheral attractions they won't complain! They take you on a bus out to the starting point, you stage up, and start in waves. The first hour is pre-dawn and really fun.
Highlight: the course because you run though backlots, and through empty Disney themeparks. I wouldn't call it challenging.
Lowpoint: the course because you run through backlots and empty Disney theme parks. I wouldn't call it challenging.
A few marathon/disney fanatics like to run the half marathon the day before and run the marathon the day of. They get a special shirt and medal for that, but Disney characters on my shirt are not my favorite image so it didn't seem worth it.
Have fun, and have stop at one of the restaurants in the Epcot center afterwards. I think that was the best part of the race: being with my family eating syrup drenched post-marathon waffles. mmme