You can do either. The bottom of the kids bib is a tear off "Child Claim Check", so if you aren't running with them in hand, make sure to take that off so you can collect them from the finish area. In Jan my DW had one hand and I had the other so all 3 of us were on course at once. I'd say it really depends on your child. How well they do in crowds, how likely they are to get sidetracked by the character on course (usually have at least one as "motivation") etc.
Thank you, I will probably run with my daughter. She can walk but has trouble, she is very bow legged and her feet turn on her. She will need picked up, im sure. Hope its gets better for her. We go for another check up next week. But my son is the one i thought might want to run alone. Thats good they to that with the bibs. I know its Disney just didnt know how safe it would be not right beside them.