IMHO Mallaig has picked itself up a bit the past few years. Mrs S and I had a pleasant few days there in a pod last year.
Skye ferry would be a reasonable day out but look for the wee ferry to Inverie in Knoydart instead. You get to visit the UKs “most remote pub” and have time to explore a bit.
The walk along Loch Morar (deepest lake in the UK) is stunning and there are swimming opportunities.
Superb beaches abound. I like Camusdarach (Bens beach from Local Hero).
Be sure to visit the Church of Scotland in Arising, where Mrs S and I tied the knot.
Small Isles cruise might appeal.
Ardnamurchan point (most Westerly point of the UK mainland), you drive there through a massive caldera and there’s the lovely Sanna Sands.