Might as well throw in my 2 pesos on Gruden while I'm here.
I don't think he ever gets back into coaching, much less at TN. His job is super cush. He still gets to be close to the game but doesn't have the stress that goes with being a HC. When you really think about it, he has a ring, more $ than he needs already, and no headaches.
Furthermore, if he does return it won't be at the college level or it would only be for 3 years max until an NFL team wooed him back. A buddy of mine who is a Miami fan is convinced it fell through there because he wanted his brother named HC in waiting and they said "No". How much truth there is to that I can't really say and honestly I'm very skeptical of the whole story. If it is true, that says he just wants to get his feet wet before jumping back to the NFL and set his brother up along the way.