We did the Sky Princess cruise last June to the North Cape from Southampton. It was our 4th cruise to Norway, but by far the best itinerary. We also had fantastic weather, which helps.
I use a small mobility scooter and we had no tender ports. In fact, none of our Norwegian cruises has had any tender ports. It will tell you on the itinerary if there are any tender ports.
We don’t book ship excursions, but booked a couple of private tours.
I also booked the train from Andalsnes to Donbas which was fully accessible. We had done the Flam Railway before, but this was a lot better. It can be booked 90 days in advance directly with the operator ENTUR.
Norway is generally accessible.
you need to name the ports for info on ports, but in the meantime can look at VisitNorway.no the tourist boards very good website.