I think that is a given if he doesn't get an NFL OC gig, and I wouldn't think he'll just walk into one of those. I think there are plenty of colleges that would be more than happy to have him as a HC though. Former NFL player/head coach, leader (you see those "Fight" tee shirts? #leadership), "smart" (hey, did you know that he went to Princeton?), etc. He would be an easy sell for a a college program and I think he would even get a shot at a relatively high-profile gig if one is available when the time comes.
I'm not suggesting that he would deserve it or that he would necessarily succeed, but I think there is no question he will have that opportunity if he wants it.