Some possible routings are: Oslo>Gotenburg>Copenhagen>Hamburg>Amsterdam>Brussels>London. OR could consider going out further to say Switzerland or even Milan/Venice.
We did something like this last week, albeit heading in a different direction after Hamburg.
I appreciate that you didn't go ahead with the plan, but I thought I would add my experience in case it helps others who find this thread.
We did:
Copenhagen to Vejle
Vejle to Hamburg
Hamburg to Berlin
Berlin to Mannheim
Mannheim to Zurich
All of these were comfortable and scenic, travelling on the ICE trains at around 220-250kph.
Longest sector was ~5 hours (Berlin to Mannheim) and most of the others were around 3ish hours.
Germany required masks on the train (onboard only, not required at the station or platform), whereas Denmark and Switzerland did not.
Any suggestions on ideas? Will likely get a four day rail pass (if these are still a thing)
I wouldn't bother with a rail pass these days. Just use the app for the relevant country such as "DB Navigator" for Germany and buy the tickets electronically a few days beforehand. For cross country journeys you can use the app for either country to buy the tickets and make seat reservations.
Most trains were quite full, so I'd strongly recommend seat reservations. Apparently over the summer it was even busier.
Reservations are simple via the app, and only a few Euros extra. Worth it.




