President Obama ridiculed him to his face at the Correspondent's Dinner a few years back. The campaign is a Fuck You to Obama and the rest of the establishment that laughed at him as a lightweight.
He worked very hard and won and now he'll be improvising. He'll have to pay back some people that supported his campaign, many of whom have specific political goals. He'll allow them to work towards those. But apart from a big tax cut for the very rich (strangely) I'm almost certain see that he doesn't care much at all about the rest of his platform. Certainly not the Christian-right stuff.
Maybe he has a real conviction about trade deals. It'll be interesting to see if he moves the needle on any meaningful trade metrics.
That's just my personal impression from listening to him talk.