Lübeck is definitively worth a visit. If you need more information, I am happy to assist you, since my parents have been living there for more then 20 years.

You can fly into Hamburg, see the MiniaturWunderland and the harbor there. Then it’s easy to go to Lübeck by train.

Next from Lübeck to Wuppertal will take you around 4 – 5 hours by train. I would recommend to just do the monorail-ride there and skip the rest of Wuppertal and continue to Cologne for an overnight stay.

Continue from Cologne direction Munich by train along the Rhine river and see the castles there (caution, do not take the fast train, which does not go along the Rhine).

Stay in Munich and visit Neuschwanstein in a day trip from Munich.