I don't know if they have regular pb&j's anywhere, but they sell those Smuckers Uncrustables all over the park and resorts. I only saw them with the grape jelly.
While most locations offer Smucker's Uncrustables, some locations use rainbow bread. I am about 90% sure that grape is the only kind of jelly available, although if it's really important to your dd to have strawberry or apple or a jam or preserve rather than jelly, there's nothing wrong with bringing a small jar of your own along for the trip.