Ugh, there's no clear Anti-Trump.
He'd pretty clearly win a 2-way with either, especially with Cruz.
Not sure about pretty clearly; I think portions of Pennsylvania are Midwestern enough in their culture, as opposed to Northeastern, that Kasich and Cruz voters should prefer each other to trump. I don't think trump could win a 1-on-1 here. With either.
Yep, what Gass said plus I'd add that the only other place he struggles outside the city limits of Pittsburgh are the northeastern leaning parts of the state, which he has a decent shot at in a 3 way (and as I said, Cruz doesn't have a prayer here, it's Kasich that is stronger than he is as you go north).