Since you think Rand would ideologically support Cruz after deriding Reagan on abortion, I have to consider you not to be much of an authority on her.
It is very easy to analyze the 2016 campaigns and campaigners but very hard to actually observe what is going on and all projections are arbitrary. I've never seen anything like this is presidential politics.
If Cruz drops out it will be because of his up in the air citizenship status. He may be the citizen of no country at all because he renounced his Canadian citizenship (2014). His parents declared him Canadian at birth.