Board Thread:Suggestions forum/@comment-27598543-20160112212206/@comment-26172435-20160112224230

I sympathize with the notion, but I guess the current way these mountains generate imply that they also are subject to generation of structures and mobs that spawn anywhere else in the biomes they are in. Only way to avoid this decently is by creating dedicated biomes for those mountains, each with their own structure and mob spawning conditions. But I'm afraid that option is restricted by the actual scalability of the world generation map that is used in the mod. The smallest possible structures that can be generated as a biome are the preset rivers, and their width exceeds the base of mountains with an acceptably realistic slope ...

There are alternative ways, but they will likely end up messy and/or laborious.