I think without a doubt Trump will pick up more traditional Dem votes than any R candidate since Reagan. He will pull a higher than normal percentage of the union vote and minorities because they feel he will bring jobs back to America. To win he needs enough D votes to make up for the R’s that will stay home because he is the candidate.
I doubt if there’ll be as many Republicans and Republican-leaning Independents staying at home as the pundits and pollsters might think if Don Trump is the nominee.