It’s worth noting that the same poll showed a comfortable victory in Utah for either Cruz or Kasich. IOW, at least according to this one poll, a Trump nomination has the potential to scramble the electoral map. If Trump puts Utah into play, then a Trump nomination has the potential to make Goldwater’s 1964 loss look like a pleasant walk in the park.
All that said, I will believe that Utah would vote Democratic against Trump when I see it.
The nearest analogy I can find is 1992 when George HW Bush came in first, Perot second and Clinton third. If (and I think this is likely) there’s a three way contest, whoever the Republican establishment puts up against Trump will win in Utah.