They can be bused anywhere and have multiple weeks to pull this off. Keep in mind there were about about same number of total Republican as total Democrat votes in the Primary (28 Million). Trump had about 13 Million. Hillary about 15 Million.
Parties know if someone has voted yet or not. Democrats go door to door/call to be sure they get that person to vote. If not, they probably have someone go in and vote for them (assuming ID is not needed).
I have no doubt Democrats will show up in large numbers... it is what they do.
And I truly believe that, once in the privacy of the voting booth, many of them will vote Trump...
The Revolution is ON!
Vote Trump!