I drove this part when I was on a longer trip (Oslo-Horten-Moss-Oslo)And as you said it is a really fun part with lots of corners. Really recommended! Son and Drøbak are really charming places and a little stop here is a must. Thanks for the tip, TeeBee!
Fun, fun, fun (for those who like corners).
The route takes you through farm-country, with little traffic.
Lots of corner-combinations, some real hairpins.
Note that in the beginning of the season the road-surface may be damaged
from winter frost.
Son is charming small town with good art galleries and a couple of good cafes.
In the Summer it is also a busy sailing-port.