We just got back from two weeks in DK, NOR, and SWE. We covered a lot of ground and used the RS Scandinavia book as our "bible."
We started in Copenhagen and made our way up Bergen for the Nutshell (between Bergen and Oslo). We got to Bergen by traveling by train up Jutland to Hirtshals (northern tip of Denmark). Along the way we stopped in Odense and Aarhus - several neat things to see there. We took a ferry (12 hours, overnight) to Stavanger, then flew from Stavanger to Bergen. The Nutshell package is awesome, even in the misty Fall weather in October.
But... the ferry ride was ROUGH. 12 hours of 15 foot swells meant you could hardly stay on the bed without falling off. It was that way the entire trip - there was a hurricane in the North Sea that night. So we didn't sleep and were somewhat tired when we arrived in Bergen.
My advice - FLY from Copenhagen to Bergen (you may have to go thru Stavanger). Otherwise you'll spend a precious day-plus on ships and trains - which is not bad, but not desirable if you only have 7 days.
Copenhagen is awesome - we started and ended their. The Nutshell tour was our second most enjoyable part of the trip. So if you can work an efficient flight itinerary - go for it. If not, train and ferry take a lot of time - Norway is a big country! You could spend 7 days easily in DK taking day trips out of Copenhagen on the trains... the rail pass is a real bargain. Enjoy!