You can park just off the road on the west side of the bridge or at about 963,914 on the other side. Security wise it should be fine but it is usually a good idea to let the police know you're leaving it there. Gairloch Police: 01445 712017.

The best place of all would be the car park at 953,898.

Herb 

The track down the side of the Gruinard River is also suitable for a mountain bike although the last time I was there a sign further down said something about no bicycles beyond this point. However I just ignored it. I have used this route twice to get to different Corbetts.

By the way there is a boggy path at the start of Loch na Sealga but it disappears and then some rough walking