I can't figure out whether Trump is too dumb to know he doesn't stand a chance in a general election or too smart for his own good and is intentionally sabotaging the GOP.
Here are my predictions:
In the latter case he's stirring up enough chaos that the Democrats slide in for an easy win and the Democratic primary becomes the de facto main event.
In the former case I think he's actually running for VP, whether he knows it or not:
He's pissed off enough of the GOP establishment, and proven beyond all doubt that he can't get the independent vote. Normally that would just mean he doesn't get the nomination but he has enough money to self-fund and trigger the spoiler effect on the GOP unless he's bluffing about running as independent. The GOP knows this, so until they learn he's actually bluffing their only option is to both keep him happy (by giving him something - hello money-in-politics!) and not giving him the POTUS nomination. That means Trump as VP and a young-ish, moderate candidate who is unlikely to die in office and leave him in the big chair. And thus we arrive at our standard "VP as insurance against terminating POTUS early" policy.