Terrain Tiles and Recreating the World of Warcraft to Exact Scale

Level 8
Oct 1, 2010
OK I am in a small dilema. I've never made a new terrain from scratch before and I was wondering if anyone had some advice on how to make an exact replica for the World of Warcraft Cataclysm map?

My idea is to somehow apply the largest grid used in the world editor (or use a custom grid by using tiles ex. 15X15 tiles would be = to one grid) but I have no idea how I would scale this to a map of the World of Warcraft.

Anyone know how I might go about doing this?