I asked a well-informed progressive PA. elected official: Who should Democrats be supporting for Governor? He said "Tom Wolf".
Tom Wolf is the CEO of a large family-owned distributor of building materials in York PA. He was Ed Rendell's Revenue Secretary and has led many efforts to reform PA.'s business tax system. He is also a philanthropist who has been involved in many many community-oriented efforts in south-central PA.
He has a PhD from MIT, as well as a degree from Dartmouth. More at the link.