Aparently there are 107 miles of cycleable paths and tracks around Aberfoyle.
Did the loop to the south of Loch Ard from Milton back in the autum with the wee one. A more perfect Autumn day you could not have asked for.
The Loch Katrine loop cn be done but bear in mind you need to go over the Dukes at some point. The road round Katrine is not a loop and you need to head back from Stronachlachar by road. You can of course divert onto the forest roads at several points. If your keen you can miss out the Dukes by returning to the car park at Katrine via Ledard and Ben Venue !
Another i fancy is from Kinlochard to Cailness on the banks of Loch Lomond. The descent to Cailness is mental fast i have been told. Then its up the WHW to Inversnaid and back by road to Kinlochleven. Or you can take the WHW south to Rowardennan then the Ben Lomond path up to and then across Moin Eich and back into the Loch Ard forest.
It has to be said that these routes are not an easy return to the bike by any means. Simply stunning scenery on all of them though.