Hello, Ana!
Strollers are no longer allowed on-course during any runDisney race events. This new policy has been implemented to keep all participants safe while running.
You can still have a great time as a family with the new expansion and emphasis runDisney has placed on its Kids' Races. Whether in diapers, or old enough for the Mickey Mile, all your little ones can get in on the running action. And for those in the family over the age of five, the runDisney 5k's are still great fun for the family.
There is still availability for both the Royal Family 5k and the Kids' Races during the
2015 Disney Princess Half Marathon Weekend. I encourage letting the littlest of royalty in your family participate in the Kids' Races, you can even run along with them!
Thank you for sending me your question, Ana! Please let me know if I can be of any further assistant. As the runDisney Specialist on the Disney Parks Moms Panel, I am here to help.
Have a great day!
Faith