I think a lot of men who are registered as Democrats will vote Trump and the pollsters aren't picking it up.
Especially up in Rust Belt like PA, MI, OH, upstate NY...
In this, I think the "neverTrump" movement in the Republican party is helping Trump, had the GOPe lined up behind him, then it would be harder for Democrats to cross over, as most of them detest the Bushes as much as we despise the Clintons.
I’ve heard far more talk of dems voting for Trump than of reps voting for Hillary. I think those reps are going for the libertarians or just not voting at all.