I used part of this route (Kotala to Alajärvi) on my way from Jyvaskyla to Pietarsaari. Then I took through Lappajärvi, Kortesjärvi and Pannainen.
Very worthy, thanks for the tip.
From Tampere or from Jyväskylä to north the roads are mostly quite booring and its not easy to find any good and interesting roads.
Well, heres my recommendation for the way to Middle- and North-Botnia (Kokkola/ Vattajanniemi oe Kalajoki sand beaches).
This is Mostly small countryside roads. Some very nice scenery on the way, small villages and much more to see! No Big cities at all!!
You might even get surprised about some corners and curves every now and then!