Start at the National Park car park and follow the cycle path south. You follow the road for about 1 mile before the path takes you down away from the road and along the Loch.
When you get to Inverbeg cross the A82 and follow the sign up Glen Douglas which stats with a lung bustin hill, after that follow the metaled road through the undulating Glen.
At the end of the Glen turn right just before the railway line and follow the land rover track. There are a few tricky climbs as you follow the track back towards the start.
The track finishes and you turn down the hill then left along the main road for a couple of hundred meters to the tea rooms for scoff.
Not too technical, but a good work out and AMAZING scenery.