Trump is riding a momentum in the last few days of this election not so much by what he's doing, but by how enthusiastic voters think of Hillary.
Trump still faces the demographic challenge though and the main one is now the white female one. This is a block of voters that the Republicans usually beat the Democrats, but Hillary is leading Trump by 7 points. There is no more mathematically impactful voting block. The ones that put the Democrats over the top are Blacks and Hispanics. With that edge in white females Hillary may not need that Obama coalition as much as Caribny feels. That said, the Hispanic Block is surging and Blacks may yet turn out in large numbers despite the poor showing in early voting in some States and voter suppression tactics.
Trump's soft ceiling remains at around 40% and the two Independent candidates will eke out 4% of the votes, but not much to influence the battleground States. What this means is that all this talk about Trump's surge must produce an 8% swing for Trump to win. That's a tall order in the last week of campaigning.
Hillary has her 18 Firewall States with 226 Electoral Votes (New York, California, Illinois, etc.) Trump's equivalent is 14 States at 150 Electoral College votes. Even if you stretch the imagination and give Trump Florida, Ohio and Pennsylvania (a total of 47 Electoral College votes) and give him 9 other States leaning Republican (34 Electoral College votes), that puts him at 231. That is his hard ceiling. Hillary ends up with 307 Electoral College votes. That's 17 more votes than the bell weather Nate Silver 538 site.
It's the down ballot votes I believe Hillary's lack of enthusiasm may hurt, but with the all-important white female block the Dems may still get the +5 Senate seats needed to get back the Senate. I don't think they can take the House back but will pick up close to 10 seats. Gerrymandering!!