Originally Posted by You
Get two side by side interior cabins, book one kid with each parent (required), set down firm rules for leaving cabin/answering door/locking door/noise/roughousing,etc, and let the kids have their own space. Make sure that the cabins are not separated by a fire door and sometimes you can get a cabin in the bow/aft that is on a private hallway. I also bring my baby monitor for nights and discrete checkins during the day. You'll have a much better cruise too.
Actually, the cruise line's rules do allow minors to stay in a cabin without adults if their parents are in another cabin on the ship.
But the better solution here would be either (1) a small suite, in which the boys could sleep in the bedroom (twin bed configuration) and the parents could sleep on the sleep sofa in the main room, or (2) interconnecting inside cabins (the boys would have one cabin, with the twin bed configuration, while the parents have the other, with the queen bed configuration). Two adults and two pre-teens in a standard cabin would be rather cramped at best, and the boys would have no space to move about and release energy.
And on a more practical note, I suspect that most families of four would be happier with the latter configuration because it provides two complete heads so two people can shower, or whatever, simultaneously. This would facilitate matters at critical times like when getting ready to leave the ship in port or when getting ready for dinner.