Actually, you cannot get nominated with some support or acquiescence from the party.
I suppose we will see, the Convention is quite a jump from here. Most of the candidate jockeying occurs when the primaries begin.
But I don’t see where Trump has any more political support from the party right now, then Cruz has.
The GOP set up the primaries in many places to be winner take all and/or open, thinking that would favor the supposed “moderate” GOPe candidate. What they didn’t count on is someone like Trump, who has appeal to independents and even some Dems as well as conservatives, and is now the frontrunner with a plurality. I think it’s entirely possible Trump will have an outright majority of delegates by the time the convention rolls around.