If you're willing to get up early, you can take the official race transportation with them to the starting area and hang out with them until they head to the Corrals. Once they leave you can take the monorail to the Magic Kingdom and see them there (you'll likely have a 1-2 hour wait depending on their pace). No ticket required.
You can then take the monorail back to Epcot and either catch them right before they enter the park, in the park near Spaceship Earth (required a park ticket) or just walk back to the finish area.