How to play massive maps w/out lag?

Good idea monkey. I will create a new resource that is only needed to build a trade port and it must be near the city. I will selectively place them on the isolated islands unconnected from all civ capitols by the ocean. That way if there is no allied capitol that connects to my cities I or the AI can still trade.

In a sense its as if i was adding another capitol city to the map due to my settings and rules. I wasnt gonna build wonders because i know how awesome the AI is. They will stack all the trading wonders in the same city and not get any benefits lol.

You can also combine the requires water and the requires river flag to limit the amount of harbors.