The obvious choice is Michigan, but I'm going to say Penn State at home October 26.
Michigan State's road schedule is an absolute nightmare next year. They have Rutgers, but their other 4 are Michigan, Ohio State, Wisconsin and Northwestern.
Winning any of those is going to be a really, really tall task. That said, the home schedule, aside from Penn State, looks very manageable (sorry season ticket holders): Tulsa, WMU, Arizona State, Indiana, Illinois, Maryland.
If MSU can win that Penn State game, that gives us some leeway, we can hopefully win our other home games, and maybe pull one road upset? Get to 9-3. Lose that Penn State game? Then you almost have to pull a road upset, or you damn well have to avoid a single letdown game at home, or suddenly bowl eligibility comes into question. To me, that home game against Penn State seems to be the swing between competing for a top non NY6 bowl, and maybe fighting for bowl eligibility.