If Wolf wins by ~22 as some polls suggest, he will likely win most (perhaps all) of these counties:
Cameron (2006: 52-48 Santorum)
Clarion (2006: 53-47 Santorum)
Crawford (2006: 51-49 Santorum)
Huntingdon (2006: 54-46 Santorum, but less than 1,000 vote margin)
McKean (2006: 54-46 Santorum, but less than 1,000 vote margin)
Montour (2006: 54-46 Santorum, but less than 500 vote margin)
Pike (2006: 52-48 Santorum)
Sullivan (2006: 53-47 Santorum)
Susquehanna (2006: 51-49 Santorum)
Venango (2006: 52-48 Santorum)
Wayne (2006: 53-47 Santorum)
However, should Wolf only win by ~15 points, which I think is more likely, as it assumes a "coming home" effect from some moderate republicans returning to Corbett's column as the election gets closer, Corbett would retain all of the above counties, and likely win most (perhaps all) of these counties:
Armstrong (2006: Casey 50-50)
Columbia (2006: Casey 51-49)
Dauphin (2006: Casey 53-47)
Forest (2006: Casey 52-48)
Indiana (2006: Casey 53-47)
Northumberland (2006: Casey 50-50)
Somerset (2006: Casey 51-49)
Warren (2006: Casey 51-49)
Uniform swing doesn't exist, especially at the county level. Casey had more appeal in Pennsyltucky and Western PA than Wolf ever will. Wolf will make up for this loss by crushing Corbett in Eastern PA, even more than Casey crushed Santorum by.