Hi Amber!
Thank you for bringing your question to the Disney Parks Moms Panel!
This will be such a special weekend for your family!
My favorite place for people to stand is inside the Magic Kingdom, along Main Street U.S.A. (no ticket required for them)
Be sure to check out the "SPECTATOR" tab on the
Princess Half Marathon website. It has information on viewing areas and how to get to them. You will also find spectator information in the Official Event Guide that will come out a few weeks before your race. You can view it online and there will also be books at packet pick-up.
Also in the SPECTATOR tab is information about buying ChEAR Squad packages. You don't have to have them to view runners, but they do offer some preferred seating and other perks if you're interested.
While the race is very exciting, be sure to take some things to keep your kids occupied as they wait to see you. (iPads, coloring books, etc.---you know the drill!)
I hope this helps! Please let me know if you have any other questions as you prepare for Princess!