Mull, in particular, is a brilliant destination for keen hikers.
The island has one Munro, Ben More (not to be confused with another Ben More in Loch Lomond and the Trossachs National Park, or Ben More Assynt in Sutherland...). You can climb this by taking a rough and, at times, rocky path up from Dhiseig and back. The views from the summit on a clear day are particularly special.
Besides Ben More, there are a huge range of walks on Mull for all abilities - it's a wonderful destination for any keen hiker to spend a few days. We also love the route up Spienne Mor from Loch Frisa, the walk to Quinish Point, a headland accessible via a relatively flat route from the village of Dervaig, the Carsaig Arches, and if we're feeling brave, the challenging coastal route to MacCulloch's Fossil Tree.