The family stayed five days at the Hotel Kronprinz, near the Elbe River docks and the main Hamburg train station, where they booked a room for Rosa and the children, a single room for Clara Spaulding, and a suite with parlor and alcove for Sam and Livy. “What a paradise this land is!” Sam wrote Howells. “What clean clothes, what good faces, what tranquil contentment, what prosperity, what genuine freedom, what superb government! And I am so happy, for I am responsible for none of it. I am only here to enjoy.

Sam and his entourage slowly migrated to the southwest over the next week, overnighting in Hanover, where Sam and Clara Spaulding attended a performance of the comic opera Roberto il Diarolo; Gottingen, Kassel, and Wilhelmshéhe; and Frankfurt, where the family toured the Goethe Geburtshaus in the Altstadt and again crossed paths with Frank Mason, the U.S. consul general there and former editor of the Cleveland Leader.  [ Page 249 The Life of Mark Twain - The Middle Years 1871-1891]

The Clemens party took rooms at the Hotel Schloss in Heidelberg from May 6 to July 23 of 1878.

From Chapter 2 of A Tramp Abroad: At Heidelberg

The Clemens party left Heidelberg on 23 July 1878 and proceeded to Baden-Baden, where they would meet Joe Twichell on 1 August.

Twain hired the portier of the Schloss Hotel, Georg Burk, as courier for $55/month and expenses and departed Heildelberg by train for Baden.

There are two possible railway lines that could have been used for this trip:

Compared to the university town, Baden-Baden was a disappointment. Still engrossed in furnishing the Hartford house, Livy spent much of her time in the shops.

August 12 Monday – The men left Baden Baden by rail and arrived at Lucerne, Switzerland where they joined Livy, the children and the rest of the party who had been there a few days.

The German railway, Mannheim-Karlsruhe-Basel railway, and the Swiss, Swiss Central Railway.

Munich German city. Midway through the long European trip that Mark Twain undertook in order to write A Tramp Abroad, he and his family stayed in this Bavarian capital from November 15, 1878 through February 27, 1879. Members of the family regarded the Munich months as a pleasant winter rest, during which they busied themselves with studying German and art instruction and enjoyed a Bavarian Christmas, while Mark Twain worked on his book. He did write at least one chapter about Munich, but omitted it from the final manuscript.

February 27 Thursday – The Clemens family left Munich by rail for Paris, France. Sam had planned to leave at 6:40 AM and travel to Strasburg (at that time in Germany) by 5:30 PM and spend the night there, continuing on to Paris on Feb. 28 [MTLE 4: 29]. Sam noted “Feb 27, at Strasburg” in his notebook [2: 292].