I also played as Dorne before Aegon’s invasion and tried to find a way of assassinating the dragon riders before they came with their armies to burn my home. I played as John Snow on the wall fighting to restore Winterfell to the Starks. I can’t say how many hours I’ve put into that game already.
You try to acquire land, gain titles, raise a family to be proud of, find suitable marriage arrangements for your family, scheme, plot, war. If you are not familiar with the game, the essentials of Crusader Kings is that you take control of a family in Westeros (Yes, any family) and you play it. If you would really like to experience what it like to rule a great or minor house in Westeros, I highly recommend a Game of Thrones mod for Crusader Kings 2.