Hi Edward!
Congratulations on signing up for your first half marathon! Disney World is the perfect place to run!
What time you finish will probably depend on what corral you start in and how fast you run. If I were you, I would do a race (10K or higher) before the half marathon to get a "placement time". If you submit a time to runDisney, you can be moved into a higher corral than if you don't submit one. This means you will begin earlier. (the first corral, corral A, is the fastest runners, B is the second fastest, etc.) Each corral starts five or six minutes later than the one before it, so moving yourself up can save some significant time.
Here is the information about submitting a time:
Please email your updated proof of time (include the race you registered
for, your official race time, along with the year and name of the race)
to
disneysports@trackshack.com by November 1, 2012. After November 1, all proof of time updates must be made during the Expo at the Runner Relations booth.
I would think that you could definitely be back to your resort by 11 a.m. Just add your estimated start time to your estimated running time, and then about an hour for travel back to your resort.
Please let me know if you have further questions!