Last year's schedule was pretty easy, and BYU lost games they shouldn't have lost. There were plenty of winnable games during the Heaps-Nelson era, too. I think scheduling is pretty much a draw. Lots of Bronco's wins have come against the Wyomings and Colorado States of the college football world, just as LaVell's came against the UTEPs and New Mexico's of his day.
This upcoming season is an entirely different story. Definitely a schedule with P5 difficulty...