I did a circular route from Glenfinnan to Strontian and back along Loch Shiel. The climb out of Strontian involved a bit of pushing but there was a nice descent down to Polloch.
From Strontian, head up the road towards Ariundel, then left into Scotstown (you can also get here more directly from Ardnastang) where you’ll the path going over the hill to the old lead mine and then Polloch. Follow the loch to the bridge then right, past Callop farm and follow the signs up to the col and then down Cona Glen to the road (A861) at Inverscaddle Bay. From here, I just took the road along to Strontian but there is (apparently) an option to cut through Glen Gour.
There’s also a couple of miles of fun wee tracks on the side of Tom an-t Sidhean. Go from Strontian to the visitor center at Ariandel and take the main track up the river to the top bridge, cross the river then follow the track back downstream at the lower bridge, it carries on and climbs the hill a wee bit for some nice views. It’s a “walkers” path so watch out on any blind corners. before descending back down to the village.
There’s a wee cafe in Strontian and some bike hire. You should be able to get some more ideas there.