Turn down towards a church on the right side of the Clachan Inn (as you look at it) and you're onto the Southern Upland Way long-distance path. When you reach the river there's a wooden footbridge. Some dogs may find this too scary to cross because you can see down to the water. It's not a safe space for dog swimmers as water levels can suddenly rise due to a hydro-electric plant just upstream from here. The walk after the bridge is clearly signed and stays near the river for just under half-a-mile. Then cross the A762 and bear right past a passing place to stay on the Southern Upland Way for a while.  After a further mile or so the Way joins a minor no-through road for two miles until the road runs out.