The GOPe will force Trump, if he is successful with his run and is actually in it for the long haul, to leave the party and take the anti illegal campaign to a third party. Those bastards would rather lose the white house to the dems, again, then alter their course.
if the Republicans kick Trump out, I believe he could win in a 3-way race with Hillary and Jeb. It might even be easier.
Sadly, I fear you are right.