Colonel of a couple of regiments, his Heros charity, also the work that he has re Lesotho/Swaziland and then mines at large.
However, I think there is more. One scenario:
HMQ does her time and makes September then, next Christmas, hands the day duties over to Prince Chuck, remaining Queen. He becomes Prince Regent.
The Duke of Cambridge becomes Governor of Canada and Harry becomes Governor of Oz or NZ.
Another variant is that Dad and Wills become Prince Co-Regents, Harry gets his pick of the Cols......