Here are two setups that I made for lightening (I have a feeling what was originally supposed to be the fill light is taking the role of the key light and vice-versa. Struggled a bit with shadow bias’ because I couldn’t tell if anything was changing.
Here is the scene without fumbling with internal light settings too much (I used area lights instead of spotlights for the scene lights):
Also there is a spotlight against the cabin window. (I don’t think I got the glass material right since no light was coming through when I placed it inside the cabin. It does kind of a look like the window is reflecting the moon with the point light outside though 
)
After that I tried playing with the specular and diffuse reflection settings. My, sort of crummy, understanding (hailing the almighty search engine) is that those relate to how much of the full reflection from the light source is rendered when bouncing off the scenes surfaces (smooth surface reflections - direct bounce, and rough surface reflections - more spread out). Probably to an extent you could achieve the same results by toning down the lights - but I liked to keep some of those bright sheens (which turns out to be specular - I guess because its less spread out?) along the ground which I don’t think would have been possible otherwise. (Not sure if that’s realistic either, or how to make the same effect more realistically otherwise.)
Changing volume settings of the lights didn’t make any noticeable difference for me.
The result is below (also added contact shadows in this time):
