So then working on one city at a time is my best bet? huh?
Exactly. Take it slow... one location... one city... one quest at a time.
When you look at the big picture, there's a LOT to do... but when you break it up into locations... into characters... into quests, and side quests, and smaller bits and bobs you want to get done, then it's all a helluva lot easier to grasp.
It'll be a lot more rewarding, too, when you complete something and can say: "Yeah... done with that! Looks good! What's next?"