Getting onto Swanton south heading north - open areas have major undulation that is no bueno for rigid suspension. Northern section is a series of sharpish switchbacks down the hillside mainly covered in redwood with views of the ocean.
Maybe north to south would be nicer going up the tight switchbacks but then you still have to deal with the poor road quality in the farmland area.
Extremely low traffic.
A nice escapade from Hwy 1 north of Davenport. If coming from Ano Nuevo, look for Big Creek Lumber, it will be the following intersection.