I only see two near-certain wins (UTSA and Charlotte), one should-win (Rutgers), four should-be-competitive games (Nebraska, Virginia, Maryland, Purdue), two should-lose (Minnesota and Northwestern), and three near-certain losses (Wisconsin, Penn State, and Iowa).
Assuming we take the near- and should-wins, 3/4 of the competitive games, and steal a should-lose, the ceiling is 7. Assuming we lose the should-win and can't take more than two of the competitive/should-lose/near-certain losses, the floor is 4.
So that's my call. Floor of 4, ceiling of 7, and I think 5 is most likely, which will be a real bummer to miss a bowl by one game. But 6 seems...realistically within reach if a proven B1G coach can get the mojo flowing.
In any case, a win against Nebraska would set a great tone. If they're legitimately good enough to beat Nebraska, you could imagine a world where the Illini start 5-1. If they get blown out by Nebraska, you could imagine a world where they start 2-6 without an easy game left on the schedule.
I'm 2 parts excited, 1 part nervous as hell about tomorrow's game, but can't wait!