The first thing to do is send the terrain way back there and then scale it up considerably.  Then scale up your materials to match...don't forget that. I sometimes have mats all the way up to 20 in scale.

Peten's terrains are not small and close to the camera as you'll notice. When things are scaled properly, then the atmospheres and lighting (like I know anything about lighting..not) will have their desired effects....

I'm glad you are getting to where you're going....

M