Next time you should try one a lordship, its much more fun, the lower you start the higher you can rise. I never played the game before but I noticed that I had bought it on a steam sale, so inspired by you I got the mod and deciding I wanted a challenge I started as the Ryger family whose only interesting part was that it was an independed lordship of the west coast of Harrenhall. Meaning, I was not a vassal of the Harrenhall high lordship, even if I was a de jure vasal, I answered only to the king, whoever that was in these troubled times.
My independence did not last long as the Lord of Harrenhall decided to use the turmoils of the rebellion to claim me. Deciding I did not want to waste my forces fighting a superior enemy (1.5k vs 5-6k? nope). So I rolled over and swore loyalty to him as my liege, in time I would have my revenge.
I decided to use the opportunity that being in the middle of a war presented me and looked trough the lands of Kings Landing for any lordship whose castled had been recently besieged and thus weakened by the war. Finding a few nearby I send my troops to take them, as they where weak, but the money from pillaging was still very real. I also went around taking on any small groups of enemies that had been raised and was going to join the enemy, which trained my combat ability and let capture some enemies now and then. By the end of the current war for the kingdom I had netted myself a nice little fortune (Rhaegar and the rest of the Targaryen somehow survived and was allowed to keep the Dragonstone and the lordship of Summerhall).
I decided it was time to expand, using the money I had gathered I forged a claim on the lordship south of the lake Harrenhal was laying near. Then I hired a mercenary army, as my host of men was near depleted and declared war. Needless to say I won. Repeating this a few times I sat neatly on half of the lordships of the high lordships of Harrenhal. At this time I decided it was time for taking on Harrenhal itself. Taking loans to hire more mercs and forging claims I set out to take it, as it too had been weakened during the war.
I got it, but as it turns out I had only claimed the lordship, not high lordship. The current ruler simply usurped one of the other lordships from some of his other vassals. He kept doing that every time I fought him. Clearly, I would not get the high lordship by force.
I had also set my eyes on getting a Valyrian sword. I was in luck as one of the holder of such a sword was a lady. I married her in hopes that my son would inherit the sword. It would later turn out that the sword would rather stay in the family, when she died later on one of her house got the sword. Even when I killed every single person of that family did my son not inherit it, the sword simply disappeared when the house did (probably a bug, I should report it to the devs).
Well, it was at that time I discovered I could plot to take the highlordship of Harrenhal. I did. And I took it. Now, my plan to take get a valyrian sword was bust, but my wife turned out to be incredibly fertile, netting me plenty of sons and daughters. I had my heir trained by the kingsguard, he turned out to be an amazing warrior, the best in the know world with 30 points in it (I got incredibly lucky, as the kingsguard trained him to have all the right traits, formidable fighter, tall, everything).
I had also married of some of my family of to the Stark family. Now, one of my children was also quite well trained with the sword. Imagine my surprise when Cersei Lannister suggested he married her Matrilineally! Well, looking trough the family Lannister family three I discovered something interesting. The imp had been banished to the wall and the only other living member of the Lannisters was some female courtier. A plan was hatched. See, Cersei wanted him because he was one of the best warriors in the kingdom after my heir, but what she did not know was that he was chaste, he was not like to father a son. So I accepted and immediately had one of my other son marry the other remaining Lannister. With a little luck Cersei would die childless and the courtier would inherit it all and eventually her children who would be of my house (That plan ended up bust, as neither ever got any children and thus house Lannister disappeared).
I died and my heir inherited Harrenhal while some of my other siblings got the other all the lordships. This gave me the idea to do a Frey, one of my siblings that where still a courtier was quite lustful, I married him of to someone who where also lustful and started a breeding program. I then married on of the Targaryen as she had amazing stats. This made me quite invincible on the battlefield, I took quite a few lordships, which was then given to the offspring of the breeding program.
Then the old king died and shit went down. I noticed that my wife had a claim on not only the iron throne but also kings landing. I did not feel prepared to fight for the entire kingdom, but I liked the prize of kings landing. So I hired A LOT of mercs, called in my allies and used the turmoil of succession war to declare war on the king. Most of his troops was up north to deal with the rebellious Starks so I managed to take kings landing and force a peace, my wife ended up as the queen of the independed kingdom of kings landing! As the war was ending she did something incredibly stupid and declared war on the king for the high lordship of kings landing all on her own. I was not going to let all that work go down the drain, so despite being scared shirtless of the massive armies of that king I sided with her. Turns out that being the best warrior the world as ever seen helps a lot, as I roflstomped pretty much everything he threw at me, I could take on armies ten times the size of mine.
But, in the end it was a bit of a waste, as the next king simply usurped the high-lordship.
Oh, a lot more happened but in short terms when my amazing warrior died of old age the king demanded kings landing back. But I had prepared for such eventualities, I had killed of the owners of the various castles in the city and placed my family in control of them, so when I gave the red keep back to the king he would own the lordship, but I would control it. Useful for when I would set my eyes on the iron throne, which I am gonna do soon, as I am set to inherit both the North and the Westerlands, while the Riverlands is controlled by my family (both the paramount and many of the lordships and high lordships) and nearly all the great families had a Ryger in it.
As of speaking I the Ryger clan have over a hundred members, a fair portion of those have their own lands (You should see the succession wars I have all on my own. Every time I die its a race for who can get most of the family on their side in the following wars.)