They aren't going to win Montana and Idaho any time soon (and probably not Utah either).
Utah is the least likely of these states to become D, and Montana the most.
I'd say Utah is definitely more likely than Montana, but almost all of them are impossible, so "likely" doesn't mean much in this case.
Why? Montana actually does elect democrats, and I get the feeling that a lot of the mountain west isn't as great of a fit for the way the republicans are trending as some think. Not that the same doesn't apply to democrats as well...
Both parties seem to want to become eastern parties.