This route heads south from Tarbet, along the shore of Loch Lomond, to Luss and Balloch. Most of it is on paths or closed roads although some of it is alongside the very busy A82 road. This route has now been upgraded and made into an official cycle route. See Argyll & Bute Council for details. From Arden there is a branching cycle route to Helensburgh, and an option for going to Garelochhead through Glen Fruin. From Balloch there are the Sustrans routes to Glasgow via Dumbarton and to Callander via Drymen.
Head out of Tarbet on the main A82 road (using footway alongside the carriageway, which is to become the cycle path). After a mile or so there is a turning on the left marked as a No Through Road, where the footpath veers to the left. Take it. This is the old A82, now closed to motor vehicles. Head through the access barriers and follow this closed road. Continue onto the path at the end.
The path returns to the A82 to go past a caravan park entrance. Go past the entrance and over a bridge, then turn left along a path near the Inverbeg to Rowardennan ferry. Turn right and continue following the lochside path southwards, past a house. At the time of writing, this section of path is still to be upgraded. Work is proceeding on a section of path to the south of this location.
Eventually you get to the Luss loop road. Follow this road through the village. At the southern end, where the road rejoins the main A82, fork left onto the golf course access road, then fork right onto the next section of path. The path shortly returns to run alongside the A82. Follow a short deviation along the old carriageway, which returns to being a path afterwards. Go straight on at the Arden roundabout, unless you want to go to Helensburgh or Garelochhead, in which case turn right and follow the new Argyll & Bute Council cycle route up the hill, then left at another roundabout for Helensburgh or straight on through Glen Fruin for Garelochhead.
Back on the route to Balloch, turn left at the first proper junction after the Arden roundabout, where the path veers to the left. Follow this road right through, passing Duck Bay, until the mini-roundabout at the Cameron House Hotel. Go straight on onto the footpath alongside the A82. Follow this path and shortly it veers to the left and connects into a section of old road. Continue along this and it ends up in Balloch. (There are now cycle route signs inviting you to turn left at the Lomond Shores complex; you can choose for yourself whether or not to follow this slightly longer but more off-road route.) Go straight across the roundabout into Balloch Road. The station is on the right and the Sustrans National Cycle Network Route 7 cycle path to Dumbarton and Glasgow starts on the left (where the Lomond Shores route ends up), just before the bridge over the river. Continue over the bridge to take the route to Drymen and Callander.