In reply to An Triubhas:
Best route to access the CMD arête.
My choice would be from the North Face car park at Torlundy, up to the CIC Hut. Then up into Corrie Leis and finally the headwall of that corrie [may require grade 1 climbing]. This puts you at the bealach between Ben Nevis and CMD and at the start of the CMD arête proper. Then up the CMD arête onto CMD.
Great views as you pass under the cliffs of ‘The Ben’, plus as you ascend the arête.
You will meet many others coming the other-way who will ask you in surprise, where you came from. By which they mean how did you reach the ridge, not where were you born.