Well, experience points are just numbers, and "promotions" can be easily achieved through dummy buildings, so the hardest thing would be making an interface to show everything, which is not very hard.
Increasing the city range though probably would require dll modding, but I think whoward's dll already does that.
Increasing the city range though probably would require dll modding, but I think whoward's dll already does that.
Faith & +2
Culture.
City-States without becoming a Warmonger.
Golden Age. Cities deal +5
Attack Damage to enemy units.
trade route to a foreign city (it can only do this once though; it doesn't get consumed however).
defensive strength of your cities. During war, the influence resting point with
gold gifts to
food and 
Happiness (up to +20%).
Science penalty from cities doubled. +2
Production from Farms when at war and may build Farms on any Hill tile. All units receive double
Movement on Farms.
Connected to the
Capital via Railroads automatically build land infantry units when at war. Enemy units take damage if they end their turn on a Eurasian Railroad.