Oban to Isle of Mull (Craignure) by ferry, than take a coach to Fionnphort, here do you have tours to Staffa (visit fingal’s cave and Puffins. The Vikings gave it this name as it’s columnar basalt reminded them of their houses, which were built from vertically placed tree-logs) then take a ferry to Isle of Iona (there’s a option for the Staffa tours boat left you in Iona) and you’ll find restaurants, guests houses and hotels, where you can overnight and have meals. Visit the Abbey and surrounding areas, and the white sands and crystal water for some activities. Can be one or two days journey.