I have re-sculpted this entire terrain heightfield, and am in the process of laying out the new Climate/Terrain Type maps (used to blend textures, as in the previous shots). I've read up a lot on GIS and so my workflow has improved a bunch. Almost ready to get this version back into the UDK engine....
https://plus.google.com/u/0/104849355407989263028/posts/HAgLNsCAfGp