The Norwegian roads are good but they are practically all with only one route for each direction, sometimes when the terrain allow it, there is small sections with two routes to allow drivers overtaking, this means that the average speed is low and usually the people do not ride more than 90 km/h.
The support infrastructures are very good, there are many places to stop, with space for trucks and normal cars, usually with bathrooms and most of the time in very pleasant places.
Norway is a Nordic country with many months of cold, snow and ice. So you need some precautions when traveling around the country, the first is that the further inland and further north, the colder the country is and consequently more ice in the roads so it is almost mandatory to have snow chains and if possible snow tires.
It is normal to have cut roads, in Roldal for example, we caught a snowstorm and were completely stopped for two hours until we had to turn back.
To give an idea of how Norway roads are, we wanted to go from Roldal to Oslo, was 350km and the only alternative route to Oslo was a 700km journey, double the distance.
It is normal in the fjord area sometimes the road ends and we have to catch a ferrie to continue our route, but the connections are frequent and the prices are low, about 3 euros per person or something.