Starts about 5 km from Stegeborg and ends at a nice view over the water (Bråviken) near Stäk.
The last part (Rönö - Stäk) has quite a bit of gravel on the road, so if youre not planning on stopping near the water for the view, continue to Jonsberg instead, look up the Rönö - Jonsberg route.
...and as always on Vikbolandet roads - adjust your speed so you can stop for a tractor after a blind crest or corner, sometimes they take up all the road.