It really depends on a lot of factors, and that scenario has to do with the reaction of the RNC elites, and incumbents, if Trump makes it that far. I have the feeling that the RNC wants to broker the convention and take Trump out of the mix. If so, this could be the end of the RINOs and the republican party as we know it.
Yet, if the RNC gets behind Trump, I think he has a good shot at winning over Clinton. It could be a 'close one', yet I think he could pull it off.