Starting Points
Start with 2 basic references: (1) a map of PA watersheds and (2) TV markets UNAIDED BY CABLE (i.e., the "old" BROADCAST TV markets such as "Scranton/Wilkes-Barre", "Harrisburg-York-Lancaster", "Johnstown-Altoona-State College") which should educate designers as to "communities of interest" that go back decades if not centuries, so one can capture through knowledge of terrain how local people commune and communicate: live, work, and play in our regions... yet-today. Then do not "pick on" [i.e., isolate in a weird assignment to a "new" district] small jurisdictions that are rural just to "make the numbers work". Snyder and Union used to be one county in the days when a new county created by the Legislature also created a new Senator. An end was put to that charade, but you would self-counsel to know those early legislative maps before you deem to create the one for the current upcoming cycle. Keep Snyder and Union integral as it once was (and remains socio-economically) and review others from the same perspective.