My next CK2 game, played from 1066 to the end, was great. I spent about 80 years starting from Dublin to become the King of Ireland. I spent some more time replacing rebellious vassals with family members and people with a high opinion of me. Eventually, noticing Scotland eating up England and constant rebellions, I decided to swoop in and take enough of Wales to become its king. Eventually I would get all of it.
While doing this, I had the Court Chaplain kissing the Pope's ring long enough, and made a very generous donation to the Holy See, so that I could request an invasion of Scotland. With a bit of fighting I became the King of Ireland, Wales, and Scotland, although I had a lot of pissed off Scottish vassals, as well as Welsh and Irish vassals whose troops I borrowed. I also gained a claim on being the King of Portugal by fighting with the Scottish king for his territory.
I had an eye on England, though interestingly the Pope would not let me invade it because it was smaller than me at this point. I spent most of the rest of the game waiting to usurp the title of the King of Portugal from the King of England. When I finally did, this seemed to piss him off enough to look for a way to start wars with me. Slowly, my almost-empire crumbled as wars broke out one after the other. I had to implement Autonomous Vassals in Wales and Scotland as part of the terms of surrender. After that, when more wars broke out, it was impossible to revoke the titles of the traitor, even if I won. Ultimately the northern part of Scotland up to Ross became independent. At the end of the game, Norway was beginning to take over the northern part of Scotland.
Ended with 37k points, and, I think, a good first "real" try that sucked me into this game.