According the the rundisney.com site....
Magic Kingdom® Park
Spectators will be able to see their runner run through the Magic Kingdom® Park near Cinderella Castle (Mile 5.3 for the Half Marathon and Marathon). This location will be open at 5:30 a.m. You do not need a ticket to enter the Magic Kingdom® Park, but to enter the ChEAR Zone area, you will need a ChEAR Zone wristband.
To reach the Magic Kingdom® Park spectator area from Epcot®, walk from the start of the monorail station at Epcot® and ride it to the Transportation and Ticket Center. Exit the monorail, walk down the ramp and follow the overhead signs for the monorail to Magic Kingdom® Park. Ride the monorail to Magic Kingdom® Park and exit the platform heading towards the Magic Kingdom® Park entrance. Proceed through the entrance and Main Street U.S.A. toward Cinderella Castle, where you will find the spectator area.
Other Walt Disney World® Theme Parks
If you want to watch your runner in another Walt Disney World® Theme Park, you will need to purchase a Theme Park ticket once that park is open for the day. Transportation to these parks is available through the monorail and bus system at the Walt Disney World® Resort.
Finish Line
Spectators can see their runners again at the Finish Line. There will be a limited number of complimentary seats along the Finish Line available on a first-come, first-serve basis. Reserved seating is available for purchase through our ChEAR Squad.
The Finish Line is located in the Imagine Lot of Epcot®. To reach the finish line from Magic Kingdom® Park, take the monorail back to the Transportation and Ticket Center. Exit the monorail and follow the signs for the monorail to Epcot®. Ride the monorail back to Epcot® and upon arriving, walk down the ramp and exit to your left towards the parking lots. The Imagine Lot and Finish Line area will be on your right.
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Keep in mind the 1/2 goes from Epcot parking lot to MK and back. I'll be running on Saturday!!!! Good luck to your husband!
And don't forget to sign up for runner tracking to see how your husband is doing...
http://live.xacte.com/wdw/alerts/