The 2007 Fiesta Bowl team ran the ball 65% of the time. Running plays can mean a lot of things. That means QB options, RPOs, read options, QB draws, end arounds, fly sweeps, wildcat... all of which Boise has in the playbook. You're gunna see Khalil and Hightower running the ball, so there are ways to get the ball into the WRs hands without throwing it every down. They'll throw it too, but Boise has always run the ball more than they throw it. They are usually somewhere between 52-58% run heavy. Harsin's most run heavy team was 58% run... which happened to be the Fiesta Bowl team.
With the defense being a strength, a veteran OL, and an inexperienced QB, it makes sense to lean on the strengths and not rely on the most inexperienced part of the team.