Crossing is to lead off the beaten track (8)
I believe the answer is:
isolated
'off the beaten track' is the definition.
(I've seen this before)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for isolated that I've seen before include "Cut off, remote" , "'Detached, kept apart (8)'" , "Placed alone" , "Remote, set apart" , "(Left) on one's own" .)