Princess Cambridge will live in South America, her parents having taken enough cash with them to set up a nice home, and she will "come out" in society there. But, on the other hand, Prince Cambridge will be sought after as a husband for one of the many young female Crown Princesses of Europe. I am assuming there will not be a monarchy in England at the time. The "Pretenders" from the Stuart and other camps will be trying to restart a monarchy, but with little success. I am assuming we will have had WWIII and other disasters which have ended the formal monarchy in England. I know people would prefer to be positive, but I think the family Windsor will still be in privileged positions in exile, and more popular than ever.