texturing big landscapes - help with the chosen technique

Hello all,

Im looking into some help for texturising big landscapes. I ran into this technique used by Mike Pan (http://blog.mikepan.com/post/26950891126/procedural-terrain) and i liked it very much. After some experimentation i was able to make it work in cycles (well to the best of my noob knowledge at least. i stand ready for any correction).
Here is the example blend file: http://pasteall.org/blend/index.php?id=43892

Ideally, id be using the same technique on a landscape of about 400X400 meters in size, for a small animation project im trying to patch together.

What i am in a need of is some instruction (if anyone gets the time a snapshot of nodal setup) on how to add some detail to the textures. For example: im unsure how to go about adding normal maps: i tried combining them in separate channels corresponding to the textures applied, and then mapping them in the same way, but that didnt get me too far at all.

Also - its fair to say that im not sure what else would be out there in regards to adding more detail to big spaces like this one, so basically im up for any feedback.

Best regards