How would I go about getting a dump of the locations and related details (encounter rates, encounter methods) on where to obtain all the Pokemon in Black/White? Is there an existing tool for this or would I have to write my own? Where would I start?
Not sure if this is of any use to you, but it's quite convenient and may help you understand the format of the code:
If you use Zero's Wild Pokemon Editor, you can export a .txt file with all of the pokemon encounter slots, rates, and methods (grass/water/tall grass/shaking/dark(double)/fishing/whatever) in the game laid out in English.