Hi Karen!
I know that you and your daughters are going to have a great time at the kids races! My boys love them too!
Having the races at Epcot is actually new for this race weekend. They are usually at the Wide World of Sports, but there is a big ballgame there that weekend and they were worried about it being overly crowded. So, actually, right now runDisney is still working out all of the details about the races. (where they will exactly run, etc.)
You will receive a "final instructions" booklet via email a couple of weeks before the race. The booklet will also be available for download on the
Princess Half Marathon website, and in print form at the Expo. This will have ALL the information for all the races that weekend.
Please let me know if you have any trouble finding that, or any other questions!!