All very weather dependant but
– head south to Kinlochleven and take sort but steep’ish walk to the Grey Mare’s Tail. The south road along the loch is spectacular, miss the first signposted turn off, cross the Ballachulish bridge, then turn left at Glencoe village (well short of Glencoe the famous glen). GMT car park is just over the river in Kinlochleven. Signposted.
– up Glen Nevis to the car park then follow the path to the flatlands below the Ring of Steall. Energetic but not deadly.
– North East to Fort Augustus, hang about the locks and watch the boats, then onward to Urquhart Castle for some monster spotting
– like Big Engineering? Ben Cruachan is a mountaim some 60 miles drive away which was hollowed out and a 400MW hydro power station built inside it – you need to book that though. Oban has a nice wee distillery producing a decent drink, and the loop via Glen Coe, Glen Orchy, Oban and back up the coast is stunning. Lot of driving though.
Grey Mare’s Tail
Ring of Steall bridge
BTW steam train to Mallaig is pricey and views from the ordinary train are just as good. Get the steam tain timetable, get the train before the steam train to Glenfinnan, get off, head for the road and watch the steam train crossing the viaduct.