The E6 has speeds from 70km to 110km with supply trucks running up and down it all day. I personally would not cycle it but people do and it’s certainly possible. You can do Melfjordbotn without requiring much time on the E6. The journey further north to the Arctic Circle is also possible. There are two tunnels but I think you can go around both. A friend of mine did this loop a few years ago.

http://www.ridewithgps.com/routes/38725163?privacy_code=L4JfUoKP05XpeUIH