Alan - I walked that way in September. There are fields and grass S of the river at Invergarry but it all felt a bit public so I camped further west. The bunkhouse, B&B's or the hotel looked the best bet there really. I'm sure you'd be fine camping there though. Loch Lochy has some good spots especially in the SW half. From Laggan Locks to Laggan Swing Bridge there are some places but again it might feel a bit public. Hopefuly someone will come up with a perfect spot for you.

I can also recommend Faichemard Campsite http://www.faichemard-caravancamping.co.uk but this may be too far out of your way? It does, however, give easy access to the higher route of the GGW towards Fort Augustus, if that is your onwards route.

Thanks for the help ,

Have a read of this and scroll down to Sunday 14th May....there's usually SOMEWHERE to camp!