I've ridden and walked this area a bit in the past but can't remember what would be best/most spectacular as part of a long distance ride from Oban to Ft William.
My instinct was to follow the 'Ciaran Path' uphill from the dam towards the bothy but then cut left, up and over the hills, and descend towards the viewpoint and the good gravel track above Mamore Lodge. I've walked this whole track and remember it being mostly good but that was on foot, can't remember how rideable it might be.
However there is also the 'Pipeline track' which I've walked part of in the past and appears to have been used in the past (old Strava segment). Presumably this would be flatter and I imagine quite cool views with a steep drop off to your left hand side. Is it a squashy mess though?
It may be a moot point though if you can't resupply at Glencoe, last time I tried this I severely regretted not dropping into Kinlochleven and stocking up 🙄