From Hill, 1973:

The Clemens family booked passage on the Prince Oscar and left the Villa di Quarto on June 20, stopping for four days at the Hôtel de Ville in Florence. ...

The family boarded the ship June 28, ...

Then, as the Prince Oscar was preparing to leave, Clemens discovered that the death certificate and consular papers were missing.... the Hamburg-American Steamship Company had forwarded these documents to New York by an earlier ship, ...

From Hill, 1973:

On October 5, after a final visit to Susy's grave, the Clemens family moved from Elmira to New York City, where it spent the last weeks before departing at the Grosvenor Hotel....  And on the evening of the twenty-third the family boarded the Princess Irene in high hopes of Olivia's recovery and their continued financial tranquility.

From Hill, 1973:

"...Mrs. Clemens was doing so well that she and her husband decided to make a trip to Elmira in July, leaving Clara and Jean in Riverdale.  Clemens told the Huttons: 

We carried Mrs. Clemens down the hill at 8:30 in the morning, at Riverdale; lifted her into the launch and all on board Mr. Rovers's yacht, out in the river; steamed down to the DL&W dock at Hoboken, carried the madam aboard the 10 A.M. train and came through to Elmira in the suffocating heat, arriving at 4:40...

From Hill, 1973:

"When he came to move Olivia from York Harbor to Riverdale on October 15, Clemens fretted about the method of transportation:  asking for the Kanawha, then canceling the yacht and deciding on a train, arranging for a special car and special engines."

From Hill, 1973:

"Clemens' concerns over Olivia's health led him to rent a cottage in York Harbor, Maine, for the summer, where she was transported on Henry Rovers' yacht in late June."