For a guy who obsessed about football like none other while he was playing, Peyton Manning has done a pretty remarkable job of staying away from the game since his retirement. He's filmed a couple commercials and recently did a TV series where he breaks down strategy, but those are easy paychecks that take a couple afternoons at most to do. Like other posters have said, he's not even willing to do an TV analyst gig that would have him work probably 3 days a week.
He could have any front office or coaching job he wanted right now - I remember the late Bud Adams was offering him partial ownership of the Titans to come be their GM - but Manning's simply not interested. I mean, if you're turning down ownership of a team to stay retired, you are done.
It's hard to see him staying away from football forever, but if he ever does come back, it's going to be on his terms and in a situation of his choosing. Dallas OC isn't really a job that's going to move the needle.