HI - last year we did this trip, which was sensational. We few to Oslo from the UK (where we live), caught the train to Bergen the following day (fantastic!) and then the next day after taking in Bergen, caught the Hurtigruten (Norwegian post boats) line (daily sailings) up the coast to Tromso, and then, after overnighting in Tromso, flew back to Oslo and thence home.
Pace was relaxed, we got off the boat for an excursion from the foot of Gerainjerfjord to the Trollstigen pass (rejoined our ship - the Polarlys - at Molde). We spent an interesting couple of hours in Trondheim and in Svolvaer, capital of the Lofoten Islands - this followed by a brilliant sail to the bottom of Trollfjord at nearly midnight, although because of the distance north it was as bright as mid afternoon. We were lucky with the weather and were still in the Polarlys's viewing lounge at 2.00 am. Still light, it felt like early evening! The sun never set. Wonderful.
We enjoyed this trip immensely and heartily recommend it. We booked it via a local travel agent near where we lived. I was worried I'd be bored on the ship, but they work hard all the time to keep you entertained and occupied, (if you can get on one of the 'expedition' ships, so much the better) plus there are several stops a day where you can get off the ship and have a look round - only warning is be back on the ship before sailing time! It doesn't wait for you and will sail on time without you as one tardy French couple (almost) discovered!
We didn't go on to anywhere in Denmark or Sweden afterwards. Lucky enough to live fairly close by, we plan a trip to Copenhagen in May for my wife's birthday.
If I can be off any further help send me a personal message. Whichever route you go, have a great time - we did!