My guess is that he pulls a Farage and goes through with approximately 4% of his stated policy changes in terms of government overhaul.
I'm guessing that if he miraculously manages to win, he'll privately flounder for a bit before affirming to himself (and everyone else in the next press conference) that this was obvious, it's just good to know that democracy does in fact work even when gov't tries to rig everything against him, and that his fantastic temperament is going to guide him during his time in the white house, his fantastic temperament and the people of the United States...
And then he's going to go into businessman mode, because that's what he's done his whole life. He's going to act almost exactly the way he does when he's in charge of a company except with even more showmanship and probably more ego, which means he'll only go through with the stupider shit if people call him on it. If no one says 'Hah! You said you would do this and now you aren't! More reasons for me to hate you!" then he'll just not get around to it. I can see him doing a better job than we'd like to admit with foreign policy (not a great one, mind, just better than we had any expectations for), and pushing through the same sort of stuff we'd expect from a typical Republican president (since Congress would allow about that much, I figure), plus some antics and shenanigans, particularly with quite possibly a Libertarian or corporate defense lawyer Court Justice or both, probably cause quite a bit of tension, some riots and shit due to discontent at fucking Trump being president and people absolutely
flipping their shit, a prolonged legal attack on Obama and Clinton because from what I know and have heard this whole thing is quite possibly originally out of spite/anger at Obama making fun of Trump to his face at a convention where he could do nothing about it, in front of a lot of people (weird how insulting people you don't like comes around to bite you in the ass it's almost like what the people saying 'you're right but don't be a cock about it' were saying all along how very odd and unexpected), and so forth. He won't try to roll back gay marriage, or pull shit along those lines unless he feels like he needs to make a point. He's going to be very easy to manipulate accidentally, essentially. He's also pretty good at controlling image, from what I know. And you might say that's bullshit look at all the things wrong with his image but look at the fact that in this scenario he's won anyway.
Plus, once midterms hit Congress is gonna be shutting him the fuck down.
This shit isn't going to go away until conservatives stop demonizing their opponents while insisting that their side is never wrong. And the forces in the middle need to stop enabling their denial by insisting both sides are to blame. Conservatives nominated Trump not liberals. Conservatives had as their runner up a man who made a career of sabotaging the government for personal fame. Hell even Marco Rubio, the supposedly mainstream candidate, regularly attacks president Obama as being unamerican.
So, the people on the right are at fault (and always wrong), and the people in the middle are at fault, but not the people on the left (who are always innocent and correct)? (also, saying your opponent is unamerican is par for the course, I'm pretty sure Clinton's done the same thing multiple times in this cycle) Does this extend to the voters as well?
I honestly can't tell if you're doing a parody of partisan bias right now.
Sidenote: Market democracy: if you're not optimizing for winning elections then you aren't gonna be doin' shit anyway (plus they wouldn't be replaced by a fuckin' Democrat they'd be replaced by a Trump-style republican in a primary challenge)