You don't have to ride along the A82. There is a singletrack path running alongside (surprisingly fun when I rode it)that then connects with what is left of the old road (traffic free)to Altnafeadh. You join it on the south side of the A82 where the road from Glencoe village meets the main road.
The ascent is gradual this way and the scenery up through Glencoe immense. It'll give you another option to consider after you've done the north to south route. When I did it, the descent to Kinlochleven was a fantastic finale to the day. To turn around and climb back up it I imagine would be quite tough.