I asked DH, not that he is a WDW marathon expert. He said he didn't have any knowledge of that, but wouldn't be surprised only that they don't want people on the course when the parks are open as usual.
I have helped at marathons and races. I know many, for insurance reasons will say volunteers, etc are on the course until a set time (Example noon). After that you are on your own. (disclaimer)
You might look around on the Disney Dead site and see if there is someone to ask.
Just go, enjoy and do what you can to the best of your ability.
DH had *run* the last two, with each time getting worse.

The last one he was sicker than a dog half way through and said he walked the last half. And he looked pale and bad when I did meet him at the finish line. He wasn't booted out, and I am sure it took him over 5 hours to finish. Rather than his PB (personal best), it was his PW!

He has run other marathons. He enjoyed WDW the best!

DH said the only marathon he ever heard of that was VERY strict on their time limit was the Marine Corps marathon, when one year a man DIED at the start, which delayed the race. And once runners reached a certain marker, if was past a certain time, they were pulled from the race. NOW THAT'S STRICT!
The runners start EARLY at WDW. Disney has runners out there very early before the race even starts. Be prepared for Cold weather, because it is C-C-COLD!
Good luck and have FUN!
