Oban to Callander

What route?  I have cycled Callander to near crianlarich on old railway lines - the first bit is well surfaced mainly tarmac IIRC and really nice including glen ogle which is great.  After Killin the surface is worse as its not a maintained cycleroute and it disappears before Crianlarich.

There is also the old railway from North of Oban at Connell to ballachulish.  this is a sustrans route and is well surfaced but does some funny detours.  I don't see an old railway to connect the two

Edit - I can give a bit more detail if its those bits you mean - especially where to join the killin to crianlarich bit as its NOT a marked cycleway so you have to find the ends

Which old railway line? The Callander line can be picked up just East of Crianlarich and gradually wraps around the hillside to become the Callander/Killin cyclepath (which is excellent).

To get to Crianlarich you could follow back roads out of Oban via Glencruitten to Glen Lonan and Taynuilt. You're then somewhat committed to big roads until Sronmilchan where you can take a brief detour before rejoining main road at Dalmally. It's then Glen Lochy to Tyndrum and you can join the wee cyclepath to Strathfillan and maybe the WHW to Crianlarich?

The best I could find is the old railway line the whole way but I'm open to suggestions. Looking at these blogs I thought it would be jump on the line at Oban and follow it through Killin and on to Callander from there all sustrans. I'm fine with doing road sections to link the ends. Main thing is the start point Oban end point Callander

There is no old railway Oban to Killin that I know of.

you could go north to ballachulish on old railway then there is a large gap to Crianlarich where you would have to use road / WHW

That sounds like the plan. Thanks for your help

@tjagain where do you joing the Killin - Crianlarich section? Coming from Crianlarich?

Ok

so its road from Oban north to Connell and over the bridge.  Pick up the sustrans there to ballachulish.  Its then the best part of 50 miles to pick up the old railway again.  Road up thru Glencoe to the ski centre and pick up telfords parliamentary road to Bridge of Orchy,   Road or WHW to Chrianlarich and then the main road towards killin.  Best place to pick up the railway IMO is at Ledcharrie past the luib hotel.  You might be able to get on it earlier but the bridges are down and its rough IIRC.  Once on the railway its easy to callander

Edit - Geograph might have some clues about the old railway before that
https://www.geograph.org.uk/

How gravelly do you want it? There is the option of from Ballachuilish take the road along either side of Loch Leven to Kinlochleven. Avoids the A82 through Glen Coe which is a narrow road with 60-70mph traffic.

Then WHW to Auch farm just south of Bridge of Orchy. Good track up Auch Glen then south side of Loch Lyon to dam. Over into Glen Lochay. To Killin then join old railway to Callander.

I've done the Kinlochleven to Callander section ona hardtail MTB. But gravel bike would do it. Advantage over WHW from Auch to Crianlarich is a real feeling of remoteness along Loch Lyon rather than passing walkers ever 5 mins on WHW.

Edit A quick look at the map suggest the Loch Lyon route is only about 3 miles longer.

As TJ says, the line between Crianlarich and Luib isn't really there. Beyond Luib there's a missing bridge. After that it's great.

Oban  to Connell can be done mostly off-road by taking the track alongside the railway line between glencruitten golf club and connell.

If you are trying to be faithful to the Oban - Callander line and not stray into Lochaber ( 😉 ) then the Dalmally - Tyndrum section could be done on new logging tracks on the opposite side of the glen from the main road, I just don't know where they start and finish! You'd be much closer to the line of the railway that way (although this section of the line is still the main West Highland line)