Norway Itinerary Advice

Lodging in Flam is very, very tight. You may not have a lot of options at this point. Look now. I'd start with booking.com. You can also go to Google Maps, zoom way in, make a list of all the lodging options you see (not laborious; there are not that many of them), and check availability on the individual websites.

I'm not sure how much luggage you intend to take. Two suitcases--unless really large--wouldn't be too much for two people to handle, usually. I managed without difficulty, and my bag probably weighed just over 30 lb. (not recommending that, but there were reasons). I also had a tote bag and a purse, and I'm 71 years old. The various transfers you make along the Norway-in-a-Nutshell route don't involve much walking.

Norway in a Nutshell provides views down onto the fjord at Flam during the ride on the Flamsbana train, as well as views from the water during the Naeroyfjord ferry trip between Flam and Gudvangen. A trip via car would give you more views from above (which may indeed be more dramatic), but you'd need to park the car--and make round trips (potentially costly)--if you wanted to see a fjord from the water and/or take the Flamsbana. I haven't driven in Europe, much less in Norway, but I don't see a problem with either approach. The car rental probably wouldn't come cheap, but it would open up the possibility of spending the night somewhere other than Flam. I think you'll have an easier time finding lodging in a town that doesn't have public-transportation access.

We loved the west coast of Norway.
We visited Bergen while on a cruise in 2014, but hit the jackpot when we did a cruise out of Copenhagen in 2019 that went all the way up to the North Cape, visiting six ports in Norway.

By far the most awesome port was Geiranger. The fjord was amazing. Consider taking a cruise, you won't be paying sky high Norwegian prices for lodging and meals and you get to see the fjords close up.
Further, once in port, you take excursions that include The Path of the Trolls from Alesund.

I can't tell how long your total trip is, but you might consider a version of our Norway itinerary we have planned for this summer:

Fly to 0slo
Fly to Alesund, rent car
See fjords between Alesund and Trondheim (such as Gerainger)
Drop car in Trondheim
Take the Hurtigruten "cruise" from Trondheim to Bergen (it leaves in the morning and arrives the next afternoon)
Bergen
Fly home from Bergen

We are taking a total of two weeks but it could be shorter.

I interpreted the original post to mean there are only 5 or at most 6 nights available for Norway. Perhaps I am mistaken, in which case there are many possibilities.

I believe the Naeroyfjord on the Nutshell route and the Geiragerfjord farther north are considered among the most dramatic in Norway. I went to both last year, and on a shortish trip I'd choose just one of them--the one that fits best with the rest of the itinerary. In the end, the prettier of the two fjords will be the one you see on a day with good weather, so it's a roll of the dice.

Thanks everyone for your prompt responses and thoughtful suggestions. We have a total of 5-6 nights in Norway and will be visiting in mid-June. Have been able to secure a one-night accommodation in Flam. Checking to see if I can pick up a one-way car rental to do some scenic driving between Flam and Bergen, including some detours.

Hello All, I have firmed up my (mid-June) itinerary to spend two nights in Oslo, one night in Flam and two nights in Bergen. My original plan was to do the NIN with an overnight stay in Flam before proceeding to Bergen using the train/bus via the Voss route. In this case I would have done the Flam-Gudvagen trip on ferry to see the most popular fjords including the Naeroyfjord. I am now thinking of an alternate plan to take in more of the fjords and visit some less touristy sights. As per this plan, arriving in Flam by train from Oslo around 14:10, I would take the 15:30 ferry to Balestrand, spend the night in Balestrand (instead of Flam) and then proceed to Bergen by ferry the next evening (around 16:50). My understanding is that this would give me the opportunity to see more of fjords and scenic routes, though missing the spectacular Naeroyfjord. Is this a sensible and worthwhile tradeoff? Your expert opinions are welcome.