It makes sense for Colorado to go for Cruz with his stated position that the states have their own constitutional right to legalize marijuana. Trump seems to have adopted Krispy Kremes position that the first day on the job he would take Federal action to stop that.
At least thats what I think I read online somewhere that that is Trumps position, although nit necessarily on his first day.
Republicans I know who are religious enough to be Cruz supporters are militantly opposed to pot. All of them I can think of believe that banning pot at the federal level is so important that this is one case where the Tenth Amendment should be set aside.
In the early 20th century when the teetotalers banned booze at the federal level, they did it properly. They understood that the federal government had no such authority and they got an amendment to the U.S. Constitution. I have had great difficulty explaining this to local "conservatives."