Norway Roadtrip Advice

Hi everyone! My boyfriend and I are planning a roadtrip towards the end of August / Early September in Norway. We are hoping to do a roadtrip and see Fjords, Lofoten Islands, and a couple other places in between. We have 14 days total there.

How realistic is it to drive from Oslo to Lofoten Islands? Off a quick search, it seems like it is 17-20 hours drive. This doesn't seem too bad as we have done 30+ hour roadtrips before. Is there a more preferred method of travel to get there aside from flying? We would like to avoid flying and drive or take the train to get a more scenic view.

We were researching car rentals or campervans and gas seems quite expensive. So we are thinking of renting a car for the Fjords and southern areas of Norway, then take a train north to Lofoten islands and rent another car there.