I'm just going to hijack this thread temporarily to show how the region splitting will work. As it's so large, it'll be divided into four sections. This isn't the best diagram to show that, but it's the one I have, so there xD
If you want to see it without that psychedelic colouring on it, it's below.
Clearly, I haven't added any of the features yet, but you can hopefully get a clearer picture of the region as a whole.
EDIT: Well, I've been working on it, and, barring the addition of little markers for the desert and forests, here you go:
In sections here: http://i279.photobucket.com/albums/kk123/NikNaks93/DihoFull2Sectors.png