Trump is going to have his work cut out for him in managing the RNC if he manages to run its gauntlet and wrest the nomination from its hands. The people in charge now will backstab him, will leak, will do everything they can to prevent him from winning. Many of them are democrats at heart. They have that most primal fear, of losing their jobs.
Meanwhile, Trump would need the support of the party apparatus in the general election. They coordinate events, local get out the vote efforts, hire poll watchers, all the little things that will be needed for a Republican to win in an electorate that is getting dumber and more illegal. Virginia and North Carolina are tough states to win these days. So he could go in and fire a lot of people, but it might hurt his campaign. He is going to have to walk a fine line between taking control and getting them to do what he needs. It is a tough situation, controlling this organization that was taken over by the Bush family in 1989.
Once the election is over, if Trump is successful, he will need to fire everyone in the RNC and replace it with people who are conservative and don't disdain the base. Then rebuild the RNC. Then take control of the money, so that guys like Boehner and McConnell don't use money to keep control of congress. He is good at that kind of battle, I think he can win it, but first he has to get elected and then he has to clean house. If he does, it will become the kind of party where Cruz and Lee are the stars, not the hated outcasts.
But you're absolutely right about who he fires. What he'd have to be most concerned about is keeping people who would be sabotaging him.
You'll appreciate this. Was talking with a former GOP county head---big, important OH county---and he was supporting Kasich with all the usual complaints about Trump. Ultimately he said, "Well, Kasich is the only guy where I would have a job in the administration." Bingo.
If he wins the GOP nomination, I think you'll see him mount a very unorthodox campaign recruiting Dems, indies, everyone. It will likely be a complete restructuring of the GOP into a new party. Rove wanted to create a "new" GOP and completely failed. Not only lost the 2006 election, but killed Republicans for 10 years.
Whatever emerges from 2016, I think the Republicans as they now stand are finished. They can either reinvent themselves as a conservative AMERICAN party or disintegrate into a Dem-lite.