Considering going for a run over Carnethy hill and Scald Law later once it gets dark.

Sorry, no idea what conditions you may encounter (other than similar to the usual with added darkness and possibly snow/ice?) but would you mind being kind enough to explain the appeal of running over hills in the dark when you (I’m guessing here) have a bike you could do it on instead?
Thanks in advance.

It’s as close to an adventure as I have access just now and I’m in training for something.

On foot you go where you like regardless of how rough the ground, much more limited on a bike.

Different things with different pros and cons.