Hello,
If you look at the website
http://disneyworldsports.disney.go.com/dwws/en_US/marathon/listing?name=MarathonEventListingPage2
you can get lots of info and even download a map of the course.
You get to run throught the MK and it's so much fun. Still decorated for Christmas, lot's of people cheering, characters and bands along the way.

Disney was my first 1/2 marathon and it was incredible!!
The energy and the excitement was awesome. Disney can actually make running 13.1 miles fun!!!
Also check out this website:
http://www.disneyrunning.com/index,html
for lots of reports from people who have participated, including pictures.
I noticed you signed up on the WISH board and let me give you some words of encouragement. No matter how many times you "cheat" or don't exercise, keep going. And the marathon would be a perfect goal or motivation to keep on.. If there are any short races, like 5 or 10K's that you can do between now and next January, as a more short term goal, that may help keep you motivated. Everytime I don't feel like running I think about whatever upcoming race we have and I do it even if I don't "feel" like it.
These boards are a great place to get encouragement and keep motivated. I wish I had known about them 3 years a go when I set out to lose 30 pounds, 3 years a go!
Good luck and happy training !!
Angie