Two of us will start in Amsterdam Centraal on a Saturday morning, and end at Köln Hbf on Sunday (for the night train to Vienna). Hotel probably in Cologne but not definite. Can get an ICE from Amsterdam for €39.80 to Oberhausen (first stop in Germany) or €49.80 to Düsseldorf We wish to go to Düsseldorf, Wuppertal, Cologne, Bonn and maybe Aachen if it's included, and may need a locker to store luggage during the day if not passing by the hotel. There are so many tickets and zones and involve two networks VRR and VRS. I think we could just get an NRW day ticket and not think too hard, but is there a cheaper option that still covers all these cities?