I have been over to Norway many times since 1985 usually with my Land Rovers both new & old but also my P4 Rover . Remember Norway is not in the EU but is in the Schengen agreement . There is Road pricing with automatic tolls using number plate recognition. If you don't pay as you go, you will be sent the bill back to address in UK . There is no penalty for this .
In the summer weather is usually fine but there can still be snow on the highest passes but road generally are clear. I have taken a few spares with me in the 1955 Land Rover , but otherwise just had comprehensive breakdown cover.
I am planning to visit a LR meet next year organised by the Norsk LR Klubb
https://www.nlrk.no/
Previous time I went was 4 yrs ago in the old LR and travelled overnight to Hook van Holland , then drove to north Germany with another overnight stop , then to Denmark and took the ferry to Kristiansand .