yes, okay, also to MCPitman
Your 1. example is estimated done by world machine.
I agree that its these days not easy possible to create that snowy creeks and simmilar stuff using TC.
But there are possibilities to do so.
Its a matter of some custom biomes, set close to exact values like main mountain biome and give it a little lesser height.
Top block snow, some slope to smooth and for sure FromImage mode to paint at the right places.
Imagine using my adaption of Burkhards Dolomites changed at some screwes for FromImage use and see also my Lake Powell biome area for some added inspiration how to use those creeks, little canyons, valleys and so on, to create natural mountain areas any style.
Burkhards changed Dolomite area:
... and now the "Lake Powel" area:
Real world Lake Powel:
.. and some renders to show, what may be achived by my suggested workflow to realistic mountains.
Just imagine a little finetuning and some 6 to 8 more custom biomes to create that creeks, valleys, alpine pasture and everything is possible. It was created long time ago BEFORE we got that brilliant slope setting !!!!
So now, its even without any limite to get as close as you want to realistic landscape / mountains.
Its like always just a matter of turning the right amount at the right screws ... and some overall inspiration, what to use of TC´s huge possibilities, to get the wanted results.
Colored render to easy spot the changes in some custom biomes:
My point: ALL anybody may need is already provided by TC