Rand Paul is not a RINO. But neither is Cruz, either. Rubio, Rove, Romney are all RINOs.
Rand Paul is a libertarian-leaning conservative.
Rand Paul is not in league with Romney or Rove, either, as they are GOP-e, and he is not.
It comes down to this: if Cruz (for some reason) ends up not being able to win the nomination, then as a conservative, you must support Rand Paul over ANY RINO, because libertarians (though not-so-good in many areas) are always better than a RINO. Always.
Cruz is like Reagan and is rightfully visiting Ukraine, and Rand Paul is a rino.
Paul is liberal on so many issues, gay marriage, abortion, immigration, national defense, voter ID, he is trying to move the GOP into the Romney/Rove positions in a number of areas.
It is no wonder that Paul was a big supporter and campaigner for Mitt Romney.