Else, I was thinking (if it needs to be a mesh deformation) what about using a terrain generator as a base instead of redoing the entire code. I guess this would work and there are already a number of pretty good dev in BJS for procedural terrain. Coupled with say a node material and/or bumb/normal/parallax, it could end up with a nice result I suppose…
Edit: OK, may be you could start by trying to play around a little with this one:
You would just need to have a bit of imagination about the result if 
- you where to replace the heightmaps and of course the textures.
- lower or change the range of some parameters. Remove or ignore some (many actually because the project is really broad and cool).
You can already remove the trees and tweak a number of parameters that makes one think (me) that it wouldn’t be all too hard to get something out of it (just something?!…).
You would indeed need to lower all parameters, remove trees,etc… start with the threshold of geo to the lowest (not low enough:( but as you can see (imagine) pretty much everything in my opinion would be already there… and if your project is serious stuff and you’d like to use this base and technique, then may be @dunk would kindly give you a hand with it…?
