Everything is native. The only thing I changed is the number that controls me losing renown. I changed it late in the game so my renown is still only 1750 or so.
It's almost as though it's meant to happen. King Ragnar (now Lord Ragnar) brought a castle with him when he joined. The last Nord lords are all camped out in his castle as their last castle was taken by the Vegirs. Lord Ragnar and his castle are red (my faction color), but the Nord lords who hang out in his castle and come to his feasts are blue.
The only problem is the script issue that must figure out what factions are doing with regard to wars.