Winning by 3 points in an R+14 districts is a big red flag especially considering the midterm electorate in a state like Utah! If she's only winning by 3 in the district with a midterm electorate it makes me think she is toast in a Presidential year. And this whole "national star" thing is not good for her either voters want a representative not a political celebrity see Allen West, if I were her I would lay low and stay out of the spotlight.
I dunno if Presidential turnout is actually any better for Democrats in Utah. And even if it is, it's never uniform. (I remember after 2010, there was this talking point that if a Democrat survived 2010 it was just impossible that they could lose in 2012).
Romney romped in Utah because he was Mormon. There will likely be no Mormon Republican running in '16 and the district will revert back to R+3-5.