The New York Times jumped on the news here: Quinnipiac's tracking of the three crucial general election states of Florida (29 electoral votes), Pennsylvania (20), and Ohio (18), shows Trump leading Clinton by 4% in Ohio and trailing her by just 1% in Florida and Pennsylvania. Obama won all three in 2012.
If these three states flip to Trump and he retains all the states Mitt Romney carried in 2012, the final map will look like this (click to enlarge):
Of course, Trump isn't likely to carry all Romney's red states. He is most vulnerable in North Carolina (15 electoral votes), which is 21% black, home to many relocated liberal whites, and where Romney won by just 2%. Georgia (16) is another "New South" state similar to North Carolina; Romney won there by 8%.
Romney carried Arizona (11 electoral votes) by 9%. Arizona is 5% Mormon and they mostly voted for fellow Mormon Romney, but Mormons have no comparable affinity for Trump's lifestyle. Moreover, Arizona is 30% Hispanic, that is, Mexican-American, and Trump will do very poorly among Arizona's Hispanic population.
If Trump loses any one -- any -- of Romney's 2012 states, Clinton wins even if Trump carries Florida, Pennsylvania, and Ohio.