Hei hei Bryan,
Chiming in since no one else has offered anything up, but first with the huge caveat that I have not sailed in Norway. But I did live in far northern Sweden for 4 years and got over to the Norwegian coast often. I trailered over my 5.5m motorboat, and sea kayaked, around the fjords near Narvik and the Lofoten Archipelago. So I have some very general knowledge and experience, albeit on a different stretch of the cost. May be helpful, maybe not...
Familiarize yourself with sector lights, if you aren't already. Almost all the lights are red/white/green, or even multi-sector.
And remember it's Nav Region A, so channel marker colors are reversed, the cans are red and the nuns are green (Port wine is red, for returning)
Watch the tides. The malestrom is no joke. It will be impossible to make headway against, or maintain steerage with, the currents at constrictions in narrow fjords during peak flood or ebb.
Katabatic winds come up quick and can be very strong, even without glaciers nearby. A sunny and seemingly calm day can whip up into fierce winds and choppy seas, all without a cloud in the sky or front moving through.
Expect deep water and anchorages, but watch for rocks! Things are generally very well marked and charted, but it was always amazing how fast 200m of water could go to 2. Shallow outcrops and piles will often have just a metal pole sticking straight up to mark them.
Take a fishing pole! At least in the north, just jigging (with a "swedish pimple" of course) was always productive for cod and sei (pollock), and the occasional mackerel or halibut. freshwater fishing can be a mess of private licenses and regulations, but to my knowledge there are no restrictions on recreational ocean fishing (or at least weren't 10 years ago).
Enjoy the hell out of your charter. hope some of this is at least a bit useful. Let me know if you have any questions.
Lykke til og skål!
