Update: I did Rasmus' route, and very fine it was too. Recommended. Thank you again.
I didn't find the A82 cycle path on the way north, and sharing the A82 with Bank Holiday traffic was about as much fun as you'd expect, but I only had one really problemical pass, so it wasn't too bad. Coming south I did find the cycle route and that section is a mixture of very bumpy pavement next to the road, and bits of the old A82, now almost traffic free and wide and very nice. I failed to find the bakery HLaB mentions, I should have researched it in advance.
Glen Fruin is very nice. The climb is a good one, but the worst bit is at the bottom, then it just goes on for a while. Good views at the top! There are a couple of good descents (especially one on the Rosneath peninsula) as well, if you like that kind of thing.
Boyfriend completed his run, which is good, and I rode an 80-miler along Loch Awe and up to Oban on Saturday which I enjoyed.