I guess I’m done with this. I could do more but I need to get on with other things (such as work). I’m actually pretty pleased with the changes I made and the result is quite nice I think.
Using custom rocks increases the possibilities a lot. These weren’t hard to do – rough shaping in Blender and working over a bit in ZBrush. Finding a good material is a bit of a challenge. This one came from Quadspinner’s Material Development Kit.