An autumn loop around the lake
The loop is about eighteen kilometres if you skip the detour to the old pier, and a little over twenty if you don't. We didn't.
The first half follows a forestry road: wide, dry and a bit dull. After the second bridge the path narrows and runs right along the shore, which is where the birches had already turned yellow.
What I would change
Start an hour earlier. In late September the light goes quickly after five, and the last stretch through the pines gets dark long before the sky does.
Bring a thermos. There is a bench at the halfway point that seems to exist purely for tea.