So I made a little mod to strip all Kingdom, Empire, and Dukedom titles from having a holder at the 1066 start date, so the world begins with nothing but counts... though apparently, some counts have a few provinces under their belt, and they end up eating things around them rather quickly from the get go (Croatia forms rather quickly, for instance). I started as a custom ruler in Korinthos, formed several duchies in a rather extensive array of forged claims and de jure ducal claims, and holy war'd my way into control of sicily and calabria.
I've gone on to form the Kingdom of Greece with my heir, and have expanded rather rapidly through vassalization and holy war'ing greek territory from muslim Anatolia (Mirdasids). My grandson is the King of Croatia, who has been a staunch ally in my wars. The Kingdom of Taurica formed from the former duchy of Adrianapolis apparently having holy war'd through the pagan nations in that area, and I'm slowly (every ten years) claiming de jure territory from their Greek provinces.
I can currently call up about 17K in levies, with only the Kingdom of Ruthenia truly able to compete with me in terms of numbers. So I just keep beating up the Mirdasids in Holy Wars. I'm assuming that I'm correct in thinking that dishonoring my truces with them isn't a huge deal, since I don't much care what muslim rulers think of me, so I'm just tearing through their anatolian territory with gusto, waiting until my vassals stop getting pissed at me for having 'raised levies too long' before declaring yet another holy way for greek-culture territory. They've been rather effective at spreading islam though, so I'm going to have to spend some time trying to convert them back to Orthodox once I claim those provinces.
At the moment though, I'm dealing with an annoying situation. Somehow, a Tengri Vlach vassal of mine rose to power in the republic of Sicily, and since he was going to rebel anyway (103% o.O), I attempted to revoke his title to incite war and get it over with. So now I'm in a civil war with him. I've squashed his meager levies with my demesne levies and two companies of mercenaries (because I can afford it, and I'm still trying to lose the 'vassal levies raised too long' modifiers), and am now sieging my way through his territories. It's strange though, because he randomly has a city apiece in two separate counties on the Greek mainland. I'm guessing it's some funkiness from inheriting titles after I had probably granted the duchy title to whatever vassal had the highest stewardship and that vassal was a mayor. What's making it annoying is that he has obscene amounts of garrison troops (1.5k in one of his castles) and fort level (6.0 in that same castle) compared to what I've dealt with so far, so I can't just roflstomp through sieges like I have been. So it's taking large amounts of time to end this rebellion, even though there's literally no way for him to win.
Oh, and then my game randomly CTDs for the first time ever. I know my laptop is crap, and it runs terribly, but first time I've had this issue. So now I have to go through another 11 months in-game of this crap I've already had to deal with. And still hardly get anywhere. And hope that a CTD doesn't happen again.
Damn foreign pagans. Ruining all my fun.