Greetings, Sherrie!
I am excited to hear you are interested in participating in the 5K or 10K race during the Walt Disney World® Marathon Weekend held in January. First, make sure to mark your calendar for April 28th, 2015, that is when your opportunity to register for the 2016 events will begin (all races during this weekend have sold-out for 2015). And register early, the smaller races are the first to sell out.
Unfortunately, strollers are prohibited are all
runDisney race events, so being able to push your princess in a stroller along the race course, even for the smaller race events, will not be allowed.
However, there is a Disney-endorsed, in-room child care service called
Kid's Nite Out that can provide quality childcare while you enjoy the race. This service is available 24 hours a day, 7 days a week. Select the highlighted link above for more information.
I hope this helps, Sherrie. Please let me know if you have any additional questions.
Have a great day!
Faith