Yes ridden the E6 many times, Norway is fantastic but as Sneezy says you must observe limits as the are low for a reason and regularly checked. The Lofoten Islands, West of Narvic, are very nice, in fact so nice its where Norwegians holiday. A good ride is from Sweden down the King Olaf highway which runs through the Lofoten Islands.
Norway only has 5M people and 90% live South of Trondheim so straying over the limit up North you may get away with it but people will report you to their cousin, the local traffic cop, as you'll stick out like a sore thumb!
I think Norway has many similarities to riding in Scotland but it is on steroids.
Saddle up and enjoy.