I am chasing a William Heffelfinger also. Have you seen this book? I found it listed on the Genealogical Society of Pennsylvania website www.libertynet.org/gspa. Have not had a chance to access it yet.
78. 91-176967: Aughenbaugh, Gloria L.Gone to Ohio-- Ashland, Brown, Columbiana, Harrison, Jefferson, and Richland counties : from Pennsylvania counties: Adams, Cumberland, Dauphin, Franklin, Lancaster, and York, including surname index /York, PA (P.O. Box 1824, York 17405)
The descendants of Martin Heffelfinger had many Williams in it.