My biggest fear is that he'll come out and start talking about "his good friends" Hillary and Bill Clinton once he gets the nomination.
If he keeps up the drumbeat that Hillary's a old, haggard, diseased, brain-damaged old crone with a syphilitic pedophile for a husband, she'll start making unforced errors (like actually showing up at rallies and speaking), then we'll see the States like California and New York come into play and Trump winning a 45-48 state landslide.
“Be Nice to Hillary” Heaven forbid!!! Please Trump, do not fall for that trap.
If that's all you have to worry about, it's going to be an excellent year.