As part of a Cape Wrath trial by bike attempt, I pushed/rode up and over the Bealach Horn path and descended to Loch Dionard. It was a pretty grumpy hike-a-bike along the south shore but then the track back down to the main road was pleasant, easy going.
If I was going for a full traverse using the bike, I'd cycle up the Strath Dionard track, walk the south bank of the loch and up to the Bealach Horn track, then traverse and descend. Although it was a frustrating experience with the bike, the south bank of the loch did have some interesting scenery, including a very 'lost world-ish' waterfall cascading from a wee hanging corrie on Fionaven's flanks.
Disclaimer: it was too long ago to remember exactly what the south bank of the loch was like, it might be unpleasant going even without a heavily laden bike. Don't blame me if it is!