Fictional World Map Prototype Using GIMP

I have been tinkering about in GIMP trying to create a World Map for my digital comic.

The settings I have played about with are:

1. Gaussian Blur to create greyscale image layers that will then be fed into the GIMP Bump Mapping tool.
2. The GIMP Bump Mapping tool.

Anyway after 3 hours of pottering about on the laptop this is what I have:

 

Next I’m going to tweak the top ridges on the mountains and also add some text.