This is the "girl that lived about six miles away" from the HIneses at whose house Milly says she will be spending the night (375). Since that is the ruse that allows her to ride off with the circus worker, the girl may not actually exist.
When a wagon in a traveling circus gets stuck near the Hines' home, "the men" borrow tackle to move it from Doc Hines (373). One of these men, presumably, will become Joe Christmas' biological father.
