Cruise vs land tours that include Trondheim Norway

What recommendations would you suggest for several cities, including
Trondheim?

Can you specify the question a bit?

I welcome any suggestions on an itinerary. At this point I am still
researching ideas. I have never been to Norway before and looking for
some of the more popular things to do to get to know the beautiful
country. I am very active and like hiking, bike riding, sightseeing,
etc...

What do you want to see and do? Hiking, bike riding and sightseeing can be done everywhere. The Norway in a Nutshell "tour" between Oslo and Bergen is usually very popular, and for a good reason.

Is it easy to get around with public transportation?

Mostly yes.

I was thinking of starting at Oslo and working my way to Trondheim.
I have heard there are fjord tours that are lots of fun.
Tell me more about Norway in a nutshell. What does that consist of?

See the website here:
http://www.norwaynutshell.com

Some form of Norway in a Nutshell is an excellent idea. I don't think there's a better way to see some magnificent fjords in just one day--while also getting yourself from Oslo to Bergen. Rick does a good job of laying out the options in his guidebook, but it isn't as straightforward as buying one train ticket or paying for one tour. It may be helpful to read Rick's material more than once, referring to a map as you go.

Oslo and Bergen both have a lot to recommend them, and you want to include Trondheim as well (also worthwhile), so you don't have a lot of time flexibility with only about ten days to work with.

There are trains between Oslo and Trondheim; you could also fly. While I assume there are buses, it would be a long trip, so I would definitely prefer the train if you want to use ground transportation.

There are no trains between Bergen and Trondheim; too many fjords in the way. I think you could patch together buses through really beautiful country, but it would take a lot of time, and Norwegian buses don't have the advantage of being cheap. In addition, you'd be using buses that don't run very often, which would be risky on a short trip.

I don't know whether there are non-stop flights between Bergen and Trondheim; you can check on skyscanner.com. I traveled between the two cities on the Hurtigruten coastal ferry. The northbound ships depart from Bergen at around 8 PM. They get to Alesund early the next morning then make a day-long detour into the highly scenic Geirangerfjord before stopping at Alesund again that evening. The ship than travels overnight to Trondheim, arriving in the morning (before 10 AM as I recall). So it takes 2 nights and a day to get to Trondheim from Bergen. The southbound ships are on a totally different schedule, I believe, and I don't know that they take the Geirangerfjord detour.

Since the ferry is a combination of transportation plus the equivalent of two hotel nights, it is not cheap, but it is an option. Fares are date-sensitive. It may be cheaper to travel from Trondheim to Bergen than from Bergen to Trondheim.

There's good hiking just outside central Oslo and Bergen. Spending one night in Flam (along the Nutshell route) would allow for some hiking in that area, or you could rent a bike and ride down the service road near the Flamsbana rail line (not cheap). The small town of Voss, also along the Nutshell route, is known for active-sport opportunities.

Edited to add:

I'd recommend checking multi-city fares to Oslo/Trondheim, Oslo/Bergen and Trondheim/Bergen, or vice versa, to see whether you have one or more options that won't be a great deal more expensive or involve a lot more flying time than a round trip to Oslo. It would be especially great if you could fly either into or out of Trondheim, because traveling there to and from Oslo/Bergen will take a lot of time (unless you fly) and will not be cheap.

I was thinking of starting at Oslo and working my way to Trondheim.

That sounds like a good plan!

There are no trains between Bergen and Trondheim; too many fjords in
the way.

There are, but you need to go via Oslo so it will take some time. There are however bus routes along the coast as well as boats, Hurtigruten can be a great option as mentioned.

I've been in Norway before. So my plan for 2023 (March-May) is as follows: FRA-OSLO by plane, Oslo-Bodø by train (via Trondheim), Bodø-Svolvær by ferry or Hurtigruten, Svolvær around Lofoten and over the top to Narvik by rental car (or camper depending on availability). Narvik back to Bergen somehow. Bergen Oslo by train.
I have three months' time and no funding constraints. Is this feasible?
It's probably the last long trip in my lifetime and I would like to stay away from people as best as possible. I loved the short hops with Hurtigruten and enjoyed all the train rides I took. On the Lofoten, I would have liked a vehicle so I could explore at my own pace. I will avoid the tourist hits like Bergen/Alesund/Geiranger/Trollstigen and others. For me it's the travel and not the destination that's important.

Land tour plus your taking the boat from Bergen to Trondheim would give you a closer look at Norwegian people and its culture. Their social values are strongly based in respect for people and the community. Lovely lovely people.

We found Oslo to be a very cool place to explore: history, art, walking, and people are very friendly and helpful. The Norwegians were so brave in fighting the Nazis, lots to learn. Nobel Peace Center; show-stopping Oslo City Hall murals; climbing to the Opera House roof; taking a ferry out to the island with several museums (Viking ship!); Vigeland Sculpture Park; art museums; royal palace. Cool AM tour of Edvard Grieg's home.

Public transportation (air, bus, rail, ferry, tram) run like clock-work and are clean. Driving in Norway does give you more flexibility but don't believe Google on driving times; some of estimations could be too short by 2 plus hours. We decided to use public transport because we didn't want to deal with rock-slides, long hours driving, and having to map out the location of gas stations in rural areas (oops, most cars there are electric, I think)
TIP: transport is very very on time, if you're a minute late, you could miss your connection, especially ferries. arrive early to board early for scenic view.

Oslo (2- 3 nights) - Norway In A Nutshell (rail, perhaps bus too) from Oslo to Flam - stay 2 nights on Sognefyord in small village (Balestrand?, visit stave church across the fyord) - Late afternoon ferry (4 hrs) to Bergen; 1 or 2 nights in Bergen & then cruise to Trondheim.
Tip: I found an amazing genealogist on https://www.toursbylocals.com/ website for another country trip; he documented family history back to 1500's, photos, sketches, maps. Worth every penny.
.

My only complaint is that you're going and I'm not!

Thank you everyone for the great tips!!
I can't wait to go!!

Consider taking a Hurtigruten coastal ship to Trondheim.

Hurtigruten is expensive and food/drinks onboard are very expensive.

I love Trondheim! I went there 4 years ago to do research on Norway in WWWII. I flew on Icelandic Air, changing planes in Iceland. We then flew to Bergen to drop off passengers and then onto Trondheim. When you get there, you take a bus into the city. I stayed in the youth for several days before I got an unexpected home stay. it's a beautiful city that is very walkable downtown. One of its features, in addition, to the warehouses along the river with its cafes, is Nidros Cathedral where St Olaf was buried. Nearby the cathedral are several museums, one in Armory houses a whole floor devoted to Norway during the war. Up on the hill, there is a fort and great views of the city. There are many art museums, cultural events and a famous university campus to visit. One of the most stunning places I visited was an hour's north of Trondheim and is Falstad. It was the site of a large concentration camp. Today, it's a center for peace and reconciliation, but just south of the place is a forest which was a killing place for prisoners and members of the resistance. It's one of most moving places I've been to. Norway was occupied for 5 long years, the last place the Germans surrendered.

Many people just want to do Oslo and Bergen, but I recommend flying to Trondheim first, then take the train to Oslo. It's a ride I'll never forget as you go through some of most rugged mountains in Norway. I spent several days in Oslo and enjoyed all the museums there. I used their Oslo pass to get around.

Food and drinks are expensive on Hurtigruten? The excellent meals were all included on our trip. It was not an expensive trip, Bergen to Kirkenes.

Compare others to Hurtigruten, cruise lines like NCL, Royal Caribbean, HAL, celebrity.

When I compared, I found that Hurtigruten was the most expensive and you don't get a balcony. Also, most ports did not offer long excursions.