Retire in camp, honored at the 1st game, immediately made a coach, or basically any job he wants.
They cannot not take care of Troy, he is the heart and soul, even more than Bruschi.
They cannot just pad the camp roster this season - no more NFLE with 8 exemptions. Troy will either sign on somewhere else where they are really young or really thin, decide he cannot and announce his retirement in August or linger in limbo this season where he would essentially be a shadow roster emergency pickup for this team if needed - he won't sign on somewhere else past camp because he wouldn't have much value to a team whose offense and personnel he was unfamiliar with.
Whenever he officially retires you can be sure the team will do right by him. He will be honored at a game, he will be inducted into the Patriots HOF by unanimous aclimation (maybe he will run it) and he will have a job in the "organization" for life per Bob Kraft saying so too many times to count - just don't assume he will be a coach. Too little money for too many hours. Troy will carve out a spot in the expanding Kraft Group in PR/Media/Community Relations, etc. He had a 1 hour a week radio show a couple of years ago so maybe he will do some color commentary on pre and post game productions or Patriots Today or even the kids show on Sundays. The kind of job you can commute to 2-3 days a week almost like the off season program only in season...
If he's interested in coaching at all he would likely start somewhere like Marshall, where he has done some volunteer coaching and clinics in the off season. His kids are still young and his wife has a professional career too (as a chemist) where they make their full time home in I believe W. Va. He never made the mega bucks but he's averaged in the high six to low seven figures for over a decade and as his wife has said they lived on her income primarily and his was largely banked for retirement. Position coaches in the NFL start in the high fives and work their way into the low sixes putting in 60+ hour weeks for 11 months of the year. When guys still want to play they also seldom want to coach - particularly at this level - they need a little more distance from the field as they adjust to life that doesn't include personally suiting up on Sundays. Most veterans will tell you that prospect is all that makes the grind worth it. Which is why so many take a little less at the end to be somewhere where they have a shot at some playing time.
The only guy on this team I've ever heard express an interest in coaching is Vrabel, and he was very specific that his interest is in college coaching, preferably at OSU. Tedy will do PR and media and charitable work hereabouts for the rest of his lifetime. I doubt you will ever see him coaching - he can make a lot more doing media work and he's got 3 little boys he wants to spend time raising. Coaching is really for those who couldn't be or stay in the game any other way, these guys all made their mark on the field and were pretty well compensated for it.
And I don't think we need to be concerned about the Kraft's taking care of honoring any of the core guys who helped build a dynasty as they end their on field careers, nor do we have to worry that they will not be kept in some way involved with the organization as the years go by. Even if guys choose for financial reasons to finish out careers somewhere else, once they are done they will be Patriots for life.