First of all, wow that’s a stellar (pun intended) image you’ve got there! 
If you haven’t had a chance yet, give this section of rawpedia a read:
There may be a DCP for your camera already (not sure, but maybe!). Otherwise, what @paperdigits already said. Perhaps a touch of tonemapping or even simply raising shadows and increasing their tonal width a bit will help with details there.
I’m assuming you were also thinking about darkening the sky a little just around the mountain peaks as well? Not sure if it’s best approached in RT, or maybe better in something like GIMP with some masking.