There are plenty, just depends how much you’re prepared to lug your bike.
Easy route: Oban to Taynuilt, then up Loch Etive to Glen Kinglass. Ride that to Victoria Bridge, then South on the WHW to Crianlarich. Follow the old railway to Killin, then Sustrans from there to the A9 and Sustrans from there South.
Harder one: Victoria Bridge, North on WHW to Devil’s Staircase, up to the Blackwater Dam, down to Corrour and Loch Ossian. Past Peter’s Rock, ride South to Rannoch. Along the Loch and continue to the A9, go North to Bridge of Tilt. Up Glen Tilt, then head East to Braemar and continue South East from there.
