I mean, the RNC has happily gone along with him now that he’s elected, but they very much were trying to get an establishment candidate elected.
The RNC ended up screwing themselves by a rules change they made in 2012. Basically, they wanted the front runner early to look really impressive so they added a cutoff where a lot of States had proportional delegates awarded unless the winner was over something like 35% and then they would get 100%. This backfired on them when Trump was able to come in and get well under half the primary vote in a lot of states and take way more of the delegates. They were trying to cook the books for an establishment candidate and it backfired.