HI Chris,
the King Olaf Highway from Sweden down the Lofoten Islands is very good, even the Norwegians holiday in Lofoten. Yes the Leardal Tunnel has to be done it is amazing and at 24km the longest road tunnel you can ride through in the World (there are longer ones but you have to use a train). I rode through with 300 Harleys; it was an awesome experience.
Sognefjell Pass is a good ride but check snow warnings anytime of the year.
I like the 'shed' on campsites, I think they are called Heuters. But nothing in Norway comes under the heading of 'cheap'.
It is about the size of UK but only about 6million people and most of them live South of Trondheim, so anywhere North of Trondheim is sparsely populated and gives a true remote experience in Europe. Northcape is also a must on any bucket list, done it three times and would do it again if the opportunity arose.
Speed limits are low and if caught fines are horrendous, I've even heard of licenses being held and you have to exit the country! Also drink drive is zero tolerance, mind booze is so expensive you won't be drinking much anyway. Then again North of Trodheim there are very few Police or in fact anything but locals will inform on you if they think you are riding too fast. Be careful entering tunnels as wildlife often sleep inside tunnels out of the weather so as your eyes adjust to the dark you may find yourself in a herd of Sheep/Reindeer.
I really like Norway and say it is like Scotland for motorcycle touring but on steroids. It is a bit difficult to get there now, since the Newcastle/Bergen ferry stopped but well worth the effort.
Enjoy.