Scotland has so much historical interest as I am sure you will be aware. In the immediate area there is the Clan MacNab burial ground, the Crannog, Moirlannich Long House, the history of St Fillan, the Holy Loch and The Breadalbane legacy.
Portnellan has its own castle ruin on a small island on Loch Dochart. This can be explored and reached by a Canadian canoe. Other castles in the area include Inverary Castle, Blair Castle, Kilchurn Castle and Stirling Castle, even Edinburgh Castle is within a 2 hour drive.