Playing with the county of Gelre is nice to start with, if perhaps somewhat slow and boring.
You'll largely be left alone, while things around you will erupt in civil war sooner or later, giving you a good idea of how the game works regarding the dynasty and economy.
Perhaps a bit more fun would be the kingdom of Denmark in 1066, which allows you to invade some pagans and is, to my experience, not quickly engaged in wars it will not surive.