Don`t know about mountains, but i saw in a movie(interview iirc) once, a very good racing driver saying he could drive a track with his eyes closed.
Asked to demonstrate a lap, sitting in his office, he was mimicking steering/throttle/braking/gear shifts.. the "virtual" laptime was very close to his real ones.
My memory fails me now, i tried to find that video, i think it was senna or schumi, maybe someone else knows what i`m talking about.
When you learn a track, and learn it well, i think it should be a piece of cake running in pitch black. The off/on headlight trick sounds good to me, as "you" can see the opponent taillights, the problem is he doesn`t see you and might (will) take you off. Good/possible in theory, can go so wrong in practice..