Hi Rose,
Peter Pan can be a bit elusive. He can sometimes be found doing meet and greets in Magic Kingdom, either near Peter Pan's Flight or near the bridge to Adventureland. You will want to check the Times Guide or stop in City Hall when you get to Magic Kingdom to try to pinpoint his whereabouts.
If you don't want to leave the meeting to chance, you might want to think about the
Pirates and Pals Fireworks Voyage, where you will meet Captain Hook and Mr. Smee, have snacks and sail out for a great view of the Wishes fireworks show. When you dock, a certain elusive boy will greet you.
Another of my Moms Panel friends has met Pete Pan as part of the
Family Magic Tour. I haven't had a chance to experience that but if you make a reservation, I would recommend that you confirm whether Peter Pan will be part of it the day of your visit if that is your primary reason for doing the tour.
Good luck with your planning. Please let me know if there is anything else I can do to help. Enjoy!
Wilma