Edit: Upon further testing, I found that many of these statistics were incorrect because I used a stopwatch to record them, which did not account for the lag in my game. See my later posts for more accurate statistics based on the game time. Please disregard these.
Great Plains: 1.23 xp per second
Texas: 1.09 xp per second
Yucatan: 1.07 xp per second
Yukon: 1.07 xp per second
Great Lakes: (Summer and Winter have the same trade routes) 1.02 xp per second
Pampas: 0.97 xp per second
Carolina: 0.96xp per second
Patagonia (Two bays, not lake): 0.93 xp per second
Sonora: 0.92 xp per second
Rockies: 0.91 xp per second
Saguenay: 0.84 xp per second
New England: 0.80 xp per second
So, what does this all mean? Well, it can be interpreted many different ways. Say you are trying Beatnik Joe's famed BWKIC strat, or a similar one that involves getting an early trading post. Such a strategy would be very effective on a map like Great Plains, while it might not be as effective on a map like New England.
Another way it could be interpreted is that the Advanced Trading Post card is better when sent on a map like Great Plains as opposed to a map like New England.
[This message has been edited by radradrobotanks (edited 09-16-2006 @ 01:27 AM).]