Hi Codey! This is going to be my first full marathon too. I think the 20th anniversary Walt Disney World Marathon is the perfect choice!
There are several spots for your parents to see you. You can find a great description of viewing points (with clarification of whether you would need a park ticket at each point), on the
Disney World Marathon website. Just click on that link, and then click on "RUNNER INFO", and then "Official Race Program". The information for your parents will be on pages 60 and 61. You can downnload the program and print it out, or it will also be available at the runners expo in a booklet.
My favorite spectator spot, and one that your parents won't want to miss, is at mile 5.3. It is along Main Street USA inside the Magic Kingdom. They won't need a park ticket to get in as all runners and spectators will be out before the park opens for the day to the public. It's pretty emotional and magical seeing the runners run toward Cinderella Castle. It's a highlight of every race!
Please let me know if you have any trouble finding the program, or any other questions. See you real soon, and have a great race!!