It's entertaining to imagine, but I don't think Trump has a chance in the general. It's just my opinion, which is not worth the electrons needed to produce this text, but I think there are three Republicans who have a shot at the nomination. Rubio, Cruz and Trump. I think Trump has the inside track to win the nomination. I also think Trump is the least likely to beat HRC of the three. In order I see it as:
Rubio - Most acceptable to the establishment, will be attacked less, and possibly acceptable to LIVs who've had enough of Obama & Co. However, Rubio winning, however unlikely, will net the country the equivalent of Paul Ryan in the White House. A very Democrat friendly agenda, "working across the aisle".
Cruz - My pick at this point. He would make most people anywhere right of center on the political spectrum happy. But, he'll be heavily assaulted in the primaries and will be painted as a far right wing nut by the media.
Trump - Very polarizing, and raises more than a little suspicion about what he'd actually do. Too many times he seems like a game show host.