There are many great roads up into the Scottish Highlands, but planning a manageable loop from the Central Belt that fits into a day is harder than you first think. The landscape and mountains force you to follow a limited set of main arterial roads that are full of slow tourists and camper vans. Many quiet side roads I’d normally try to opt for simply come to a dead end up long valleys. As such, you’re forced into either shorter loops through some of the low lands, or very long loops North around huge mountain ranges.
This route is a loop North from Bridge of Allan to Fort William and back via Aberfeldy and is on the longer side at ~220 miles but is a great loop you can fit into a day. Albeit a longish day with about 5-6 hours of saddle time, plus stops.
The first leg takes us up through Callandar and Cranlarich to a pitstop at The Green Welly Stop in Tyndrum. The section of the A84 & A85 from Callander to Mid Lix is a great set of twisty roads skirting the side of Loch Lubnaig and then climbing up to Glen Ogle Viaduct. It can get busy with tourists peek season and the A84 is often policed, so take it steady. The A85 from Mid Lix to Tyndrum is all average speed cams, not particularly exciting, so just sit back and enjoy the scenery of Ben More, they’ll be time for more progressive riding further on.