Religion is likely a big issue here when it comes to northern whites vs. southern whites. I don't think it's regional appeal since Clinton and Trump were both New Yorkers and the fact that the Northeast didn't trend towards the GOP in 2012 for the most part (Romney was Governor of Massachusetts after all).
Trump ran a very secular campaign compared to past GOP presidents. When he started talking about God during his inauguration it me about just how little he spoke about God, Jesus, or family values on the campaign trail when compared to Romney, McCain, or Bush. This was likely a pretty big plus to whites in the northeast and upper Midwest who are much more secular than whites in the South; and also helps to explain why he did worse with suburban whites in the south vs. suburban whites in the north.
Romney is technically the former governor of MA, but he shifted further to the right in 2012 vs. 2008. Romney was also simultaneously seen to some extent as a quasi-utah candidate, rather than a proper northeasterner.
Hillary is not really seen as a New Yorker. She is just known for being associated with Bill Clinton.
She was senator of New York for nearly an entire decade.
She was that, but she was not a "New Yorker" in the sense Trump was/is.
That being said, New York is a state where celebrities and national pols can move to and become viable candidates. New York is an "elitist" state in the sense that it expects its Governors and Senators to be a cut above the crowd and not just simple folks who understand simple folks like themselves. Rick Lazio was that kind of candidate; a typical suburban GOP kid who grew up to be a lawyer and worked himself up the political ladder. He got spanked by Hillary, who would have been considered a "Carpetbagger" in any number of states. There have been exceptions to that, of course, but those are exceptions, and not norms.
