Organized NiN Tour vs piecemeal?

I wanted to spend the night in Flam so I didn't buy a "package." I bought each leg on its own.

It's the same thing. Very easy to do.

But, I wouldn't delay making these bookings. You might find somethings sold out for your time period.

BTW, I stayed at the Fretheim Hotel in Flam.

NiN isn't a "tour" in the standard sense. There are no guides or directions. You can buy the NiN components through the NiN website, or book the same transport and hotels on your own. NiN acts as an agency for one stop shopping.

If you search, there are some posts about how some have purchased components on their own. Not a good search engine on this website, but go to Norway with a search term like NiN, the filter by Travel Forum and within last year (or so).

We booked train only (no fjords or stops) quite easily through vy.No. You do have to use PayPal. The train site doesn't like US credit cards.

It's easy to buy the individual components yourself, using vy.no for the Oslo-Flam ticket and the Voss-Bergen ticket and NorwaysBest.com for the ferry ticket. For the Gudvangen-Voss bus you just pay the driver. My rough calculation in 2022 was that buying the tickets yourself saved about $100 US per person, and it's very easy once you decide when you want to travel--which you really would need to think about before buying an NiN package.

The challenging part is finding a place to sleep in the area. If you just want to spend one night along the way so it's not such a long day, Flam or Aurland is probably best. That's what Rick's guidebook recommends. In a pinch you could look for a room in Gudvangen or Voss. They're places where you switch transportation anyway, so they are logistically convenient. If you want to spend more time there, realize that, except for hiking, your options may be a bit limited if you don't rent a car. There's not a lot of bus transportation in the area, with some buses running only once a day. Before deciding to set up camp around Flam, you should check online to see what excursions exist that you might be interested and willing to pay for. I wasn't willing to pay Norwegian prices for day trips beyond the NiN transportation itself, but I think there may be some information on excursions on the NorwaysBest website. I believe one thing you can do in the area is take a ride on a RIB (inflatable boat), and I think there's a bus excursion to the Stegastein Viewpoint.

However, if you're planning to take the trip this year, I'm not sure what options you're going to find for lodging. Demand is high and supply is rather low in that area.

I am researching this for September.
There is the option of a high speed ferry from Bergen to Flam and back. Leaves Flam in the afternoon, so you can get to Flam from Oslo with plenty of time and means a few less transfers of luggage to your final destination. Norland (dot) no. is the website.
You may want to look at some of the Facebook groups. If joining a coastal ship, there will be unofficial groups specific to that ship line (Iam using Havila). Also Norway-Tips for Travellers FB group.
Possibly here, someone mentioned overnighting other than Flam....most likely Gudvangen, which is the spot where the NIN ferry switches to bus. Search for Gudvangen here and see if the comment comes up.

The express boat from Flam to Bergen does not go into the highly scenic Naeroyfjord; for that you need to take the Flam-Gudvangen ferry. By taking the express boat, you also miss out on the scenic bus trip from Gudvangen up to Voss, though I believe it is less scenic than it once was, because the route has been adjusted due to damage to a section of the road. It was still plenty scenic when I took the bus trip in 2022.

I haven't taken the express boat, but I've read that much of its path is not particularly fjord-like, because the Sognefjord widens as you approach Bergen. I've read a lot about the Nutshell route here and in guidebooks, and I've encountered no source saying the express boat is a better option than the classic Nutshell itinerary. I don't know how the fares and travel times compare, but I suspect the express boat is a bit cheaper. Time-wise, it's probably slower; it takes 5-1/2 hours, plus it runs only once a day. However, the Nutshell travel time from Flam to Bergen can vary a good bit, depending on which ferry, bus and train departures you choose.

I don't mean to suggest the express boat is not scenic, but I figured I'd probably only visit that part of Norway one time, and I wanted to choose the most scenic practical option. The Nutshell seemed easy to manage for anyone without mobility issues. I can't comment on what problems, if any, might be caused by mobility limitations.

I haven't taken the express boat, but I've read that much of its path
is not particularly fjord-like, because the Sognefjord widens as you
approach Bergen.

Most of trip is through Sognefjorden so the views are, by definition, very fjord-like. Apart from the part closest to Bergen where the boat travels along the coast.

Fair enough, but the narrower areas are more dramatic.

Thank you everyone for the replies and input! We are all booked, including an overnight in Flåm. Really looking forward to the trip!