Keep in mind that the closer your king is to a province, the higher the loyalty. This means that near the end of the game you get the dreaded bloat effect. Your empire is so big that no matter where your king is, there are bound to be outlying areas far away from him. You can solve that by putting your king in a province with a port and putting your navy all over the place. That way, most provinces are not far away by sea. Its a good idea to make sure that your most developed province has a port, because that is where your heir will teleport to when your king dies.

I wouldn't worry about money troubles too much if I were you. It is quite possible to overspend. So what? Just don't place any more purchase orders for troops or buildings until you have made more money. The point is that as long as you take care of your economy, you can outproduce your enemies.