There is a Culbertson on some maps of Path Valley, just west of Doylestown. I plan on getting over there soon to investigate, talk to some residents; Path Valley diner on 641 & 75 looks like a good place to start! On one of our drives over there we came across a Culbertson Row somewhere near the Pleasant Hall-Upper Strasburg area, but I now can't remember exactly which road it was, 533 (Orrstown Road), 997 (Cumberland Highway) or another.
I do remember hearing my grandma (Hammond/Magee, grew up in Letterkenny Twp) say something like 'from over in Culbertson" & nod her head to the north/west, she was living on Letterkenny Rd at the time. If my uncle Gerald was still with us I could ask him. He remembered all the family stuff clearly.