Hey Gundark! Yes parts of the game can port over to other games though it plays the best covering a Westeros' campaign. Combat is very deadly & uses armor as DR. Shock value is easily used in other campaign (though this is what makes it so deadly). Influence & Rep. rules could be easily be used other campaigns as well. Magic is rare & its introduction might take some work but could be done. There is a list of Npc's at the back of the book but a DM would have to put some work into making an inculsive list.
That being said I love the way GoO modified the D20 system to fit the world of Westeros! I hope that helps. Thanks Maester Luwin