Having just completed Norway, some feedback.
I made two trips to Norway.
1 - Bergen, Urnes, Naeroyfjord - May
Thursday Hamburg => Bergen => Solvorn (Ferry + Bus)
Friday Solvorn <=> Urnes (Ferry + Bike)
Saturday Solvorn => Flam => Naeroyfjord => Flam => Bergen (Bus + Ferry + Bus + Train)
Sunday Bergen => Hamburg (Flight)
* Arriving pre season meant that loads of hotels and restaurants were not opened.
* Be sure to check the ferry schedule from Solvorn to Ornes, especially outside of season.
* Flam had a huge influx of cruise tourists the day I visited. Probably less of a concern during Corona.
2 - Roros, Vega Archipelago, Lofoten, Alta, Rjukan - August
Friday Hamburg => Trondheim (Flight)
Saturday Trondheim <=> Roros (Train)
Sunday Trondheim => Brønnøysund (Train, Bus)
Monday Brønnøysund => Vega Island => Brønnøysund => Bodø (Ferry, Bike, Ferry, Flight)
Tuesday Bodø => Lofoten
Thursday Lofoten => Tromsø (Flight)
Friday Tromsø => Alta => Oslo (Flight)
Saturday Oslo <=> Rjukan (Svein and Randy)
Sunday Oslo => Hamburg (Flight)
West Norwegian Fjords - Amazing and well worth the trip to Norway.
Bergen - Loved the Northern Hanseatic town.
Urnes - Who wouldn't love this stave church on the fjord
Rjukan - Huge consistent, industrial site. Amazing to see how it all fits together.
Alta - Ranking this lower than average. It's great to see how far humans came. But I liked Tanum better. Hard to explain why.
Vega Archipelago - Exemplary island landscape.
Roros - Wooden industry town.
Struve - General complaint with Struve, should have been an intangible site. Too little tangible remains left. I climbed Lille Raipas in Alta, which gave a nice view of the area.
Tentative and Aspiring:
* Lofoten would easily be Norway's second best WHS, probably a mixed one. Great nature and the fishing tradition.
* We visited Heddal Stave Church. Should be inscribed, too. Not sure if Urnes should be turned into a serial nomination, though, as I like that it makes you travel off the beaten path.
Hotels are surprisingly cheap. I think you can get around with 60 EUR per day (or lower). Public transport and flights are also reasonable priced. The main cost driver is everything involving service. Restaurants and bars will cost you dearly. Beers go at around 10 EUR. Fast food dinner at 20 EUR. Good food way more. There are cheap options (supermarkets, 7 Elevens), but this means compromising on quality. Alternatively, you can cook on your own. If you arrive by car, best option is to bring all the food you need.
Intuitively, you would think that driving is the best option. First things first, maps skew to the poles so distances as seen by the naked eye are too small. In total, Norway stretches 1600 km North to South. Add to this that Norway has loads of fjords and mountains, so you can rarely travel a straight line and may need to take a ferry here and there. The many tunnels and bridges Norway has built help a little, but a general speed limit of 80km/h means you travel slowly in any case. Also keep in mind that the main route going North (E6) is more inland (to skip past the fjords), while most major towns are on the coast. E.g. Bronnoysund is 1h from the E6. In total, a trip from Oslo to Alta at 2000km stands at 27h.
One last thing to consider re driving in Northern Norway is that it does not naturally lend itself to driving a circle, at least as long as you stay in Norway. North of Trondheim, it's more or less down to one major road (E6) running all the way to Alta. Only viable option (before Corona) was to drive back via Sweden. Restricting yourself to Norway, you have a to make a choice between driving long distances the way up and then hopping back with smaller day trips. Or continuously driving medium distances. The option of a one way rental is prohibitively expensive.
If you don't want to drive, you are down to the following options:
* Trains run all the way North to Bodø. Their schedule is not frequent, though.
* Several express ferries exist, e.g. from Bergen to Sogndalsfjøra or from Bodø to Sandnessjøen.
* Hurtigruten is the touristy option. However, it's pricey, really slow, and the arrival/departure times are rather arbitrary. I had one connection where the boat would leave Brønnøysund at 2 a.m.
* Wideroe is a local airline that offers a sort of commuter plane with plenty of stops. Travel times are short and prices very reasonable. I used them extensively on my second trip as it's simply by far the fastest option.
A good resource for buses, trains and ferries is en-tur.no. Be sure to check your concrete travel day, as schedules may change. Do not assume that the bus/train/ferry will run at the same time on Tuesday, that it ran at on Monday. Generally, all parts of Norway are connected, but frequencies can be low (daily).
One last word of advice: Saturday is the enemy travel and planning wise. All public transport options are reduced and it's really hard to get in and out of places. If you can, try to stay in the same place.