Doing a bit of armchair navigating.
IF you wanted to get from SYH at Loch Ossian to Fort William how bike friendly is the route west round the bottom of Loch Treig
follow the Abhainn Rath over Tom an Eite and follow Water of Nevis to join the road at the carpark after the boardwalk?

Was last there twenty years ago and vaguely remember it was not a bad track up to the wire bridge and SMC hut below Ring of Steahl.
Not finding this on walkers routes is that for a good reason?

I've ridden the first half and walked/run the second!

As far as Creaguianeach Lodge you are following a vehicle track, steep and loose in places when dropping down to the loch. After that it gets trickier, lots of on/off the bike to negotiate ditches and the like. After Meanach bothy we took the track leading north to drop down to Roy Bridge, some great singletrack once you've made the climb but the estate might have bulldozed their track further along. This bit is on the Tour of Ben Nevis race so there's a route back towards Ft William through Leanachan Forest but I've not done it.

The section over the watershed at Tom an Eite and down Glen Nevis is what might best be described as "nadgery", most will be rideable but you certainly aren't going to get trail centre type flow. It's six or seven years since I've been there, but think along the lines of paths across moorland with stones/boulders at pretty regular intervals. From Steall Meadows it will be definitely hike-a-bike through the gorge and possibly the path down to the car park at the end of the road depending on the number of tourists around.

Tom an Eite is generally considered to be the wettest place in Scotland. The path, such as it Is, will take you through multiple peat hags, each involving a dismount. Taking the Tour de Ben Nevis route would be far preferable.

Thanks for the replies.
Eventually found some walking details - "I would expect it to always be rather boggy, unless you were doing it in winter when it's frozen".
Cant quite see a route Loch Ossian to pick up TOBN route but will work on it.
Trying to get to Fort Augustus without going over the Correyairack Pass.

The bit up the Abhainn Rath used to be used by the original Highland Trail route so check out some of the blogs detailing that. I'm not sure what the track from Creaguianeach Lodge following the Allt na Lairige is like but that may be an option.

Craiguianeach Lodge - Meanach - north to Lairig Leacach pop out at Spean Bridge.

Head up the A82 for about 800 metres then take a wee path to he left (through a gate). This is a very pleasant wee ride to the old railway bridge. Eventually, still on the well-made path, climb up to the Commando Monument. A quick road descent will take you to Gairlochy. It might be possible to follow the line of the old railway further down to Gairlochy, thereby cutting out most of the road section but I've not ridden it.

Or go Strath Ossian - Fersit, onto the A86 for 4-5 km and then off again at Monessie (great falls through the gorge). Trails through to Spean Bridge and then the line above.

Hopefully you can see the route from Corrour to Spean Bridge on this link https://www.strava.com/routes/11748768

Or take the easy option - Ossian back towards Loch Laggan on the big track, turn left to Fersit then pick up the East Highland way all the way to Fort Bill. would be my choice if its wet.

The abhainn rath path is OK in the dry downhill but woul dbe a miserable slog uphill in the wet. I;ve done the water shed over the glen nevis in a very dry summer and it was still a swamp. The last bit from the Steahl falls path is a hoot though.
Another dry weather option is to do the full lairig and leach trail from Loch Treig over the pass past the bothy and down to spean Bridge.

Thanks lots of suggestions to check out.
Just out of curiosity if I chose the Corrieyairack if I turn left instead of right at Kinloch Laggan/A86 can I use the track just past Aberarder Lodge up to Glenshero Lodge and pick up the GWMR there or go round the usual way past Wolftracks?

My wife ever practical says "just take the train from Corrour to FW".

Mariner wrote:Thanks lots of suggestions to check out.
Just out of curiosity if I chose the Corrieyairack if I turn left instead of right at Kinloch Laggan/A86 can I use the track just past Aberarder Lodge up to Glenshero Lodge and pick up the GWMR there or go round the usual way past Wolftracks?

I don't know, but that's the Maria Mahria Way
http://www.heritagepaths.co.uk/pathdetails.php?path=279

This route starts at the site of the former Kinlochlaggan Hotel and consistes of a rough vehicular track for the whole of its length. Just south of Glenshero Lodge enter a field via a gate to access a solidly built stile at 550931.

Sounds to be OK. Just a stile to negotiate.

Not done it but know people who have - its a good'un.