To pace yourself on a long day you should reckon an average speed of 60 kph, we dont have more than a few km of motorways or safe fast roads. We have everything else though.
I've just come back from Norway and you're not wrong about the speed limits but I'm not so sure about there not being safe fast roads. I'm a sedate rider but even I found some sections of road mind-numbingly slow for no apparent reason. I was on a loaded Dakar so hardly a speed machine.
I might go back when I'm even older than I am now but it will be in a camper van because it certainly won't hold up the traffic