Hello from Spain.
My question is whether the 28 to 31 are holidays in Germany or if they have done for these dates.
My plan is to Aachen on 28 at 15 pm and visit the historical center in the evening, go to Carolus thermen from 18:30 to 21:00.
The next day round trip to visit the city of Maastricht and Carolus thermen again from 18:30 to 21:00.
The third day in the early morning visit to the city center and take the train to Cologne about 12:00. Evening-Night visit Cologne.
The fourth day early and visit the cathedral of Cologne, collect your luggage and catch the train to Düsseldorf where we spend new years eve. In the morning of 1th january visit the downtown and the river port and 12:30 to the airport to catch a flight at 17:30 h
Is a good plan?