Drive from Dunfermline (1.5 hours). Taking the train from Crianlarich at 10:21, arriving at Corrour at 11:21. Either: a 9 mile walk from there around Loch Ossian. Or: an ascent of the Munro Beinn na Lap, 10 miles.
Return on the 18:25 train from Corrour to Crianlarich, arriving at 19:23. Drive to Dunfermline (1.5 hours).
The Loch Ossian round is on good tracks and paths, very little ascent, grade C+. Beinn na Lap is a relatively easy hillwalk but is on pathless terrain, exposed at higher levels, grade B, 570m ascent.