26th June: go over the bridge to Skye and come back to the mainland on the Kylerhea ferry. It would add nearly 20km to your day.
Yes! This! even if it means doubling back after stopping at Eilean Donan Castle.
We rode that ferry ~ 15 years ago as part of a grand circumnavigation of much of Scotland. (Aberdeenshire & relatives, Inverness, Harris & Lewis, Glasgow, Edinburgh)
In Glenelg, at the "mainland" end of the ferry, look for the Great War memorial there. [Such are everywhere in Scotland; this is one of the best we saw and a striking setting.]
And if you have a bit of extra time, there is a pair of stone brochs just down the road ...