I hear you...but the choice between Rubio and Trump is a no-brainer for any conservative.
For example, if Trump were to get elected and then decide we need a mass Amnesty, it would be very easy for Republicans to oppose him in Congress, as he flat-out lied to get elected. If Rubio got elected, he could rightly claim that people supported him, in part because of Amnesty, and will likely be able to push it through.
In this campaign season, Rubio has, at best, been wishy-washy on Amnesty, where Trump has been rock-solid.
The GOPe wants amnesty. Wish it were not so. Would not take many republican votes to get it through. Rubio would proudly sign.