Have been sailing Norway for two seasons, but mostly the more southern part. So I can't say much about the northern part. Always had cell phone connection. Since I used a foreign SIM I could pick any carrier, which does help sometimes. I'm using a masthead combi antenna, but most of the time I found the phone works almost as well without any antenna. The exception might be far offshore, where only the masthead antenna works. Going from Farsund to Tiberon in Denmark, I never lost connection and that is some 120 miles. It seems they are running double time slots on some of the cells. Going from Stavanger to Inverness I lost Norway cell phone coverage some 50 miles off, but stragenly got a signal again near the Sleipner drilling platform. In comparison I think coverage in Scotland is by far not as good. In many a loch I wcouldn't find a signal from any carrier.
Hope that helps.
Try this: http://telenormobil.no/dekninginnland/index.jsp
It's a coverage chart for Telenor Mobile, one of two providers in Norway, and also my workplace...
The other one you can find at netcom.no
I don't think you will have much trouble with your cell phone. Coverage is generally very good (both providers)
Welcome to Norway! Unfortunatly a can't meet and greet you because we're sailing in Spain this year!