I don't see him dropping out anytime soon. Every time he says or does something un-PC he gains in the polls. He still has to last to next November, but right now, I'll predict a bloodbath in Iowa and NH. By the time SC's primary rolls around I'd be surprised if there are 5 R's left.
On the D side. If Hillary hasn't been indicted, she'll win in Iowa, Bernie will take NH, I think Hillary will take SC and her and Bernie will trade states. If Hillary is forced out, Warren jumps in and the 'tard faction goes apeshit in love. She combines the worst of both Bernie and Hillary. And goes down to defeat ala Carter v Reagan.
While I will readily admit Trump is far from perfect, he's one of only five I would vote for (Cruz, Fiorina, Paul and Carson)