Instead of a summer trip to Europe, the Clemens family opted to take Candace Wheeler up on her many past invitations to revisit her Catskills retreat at the Onteora Club near Tannersville, New York.

The Clemenses…came to the Inn for the season — the father and mother, and Clara, Susy, and “Little Jean.” They took “Balsam,” a bit of cottage across the road from the Inn, and it became a sort of jewel-box for the summer — a thing that held values untold.

June 24 Monday –For Sam to have traveled to New Haven for the Yale Alumni speech of June 26,

July 8 Monday – Likely on this day Sam left Quarry Farm for New York, where he may have spent the night. He was in Hartford by July 11.  He was back in Elmira on the 24th.

June 25 Monday - Depart Hartford for New York City and Elmira

From page 547-8 The Life of Mark Twain - The Middle Years 1871-1891:

As usual, the family vacationed in the summer of 1887 at Quarry Farm, leaving Hartford on June 21, spending a week in New York, and arriving in Elmira on June 29, Sam devoted his working months at the farm to reading and writing, indulging in particular his taste for history and biography with Thomas Babington Macaulay's The History of England from the Accession of James II (1849), The Memoirs of the Duke of Saint-Simon on the Reign of Louis XIV and the Regency (1857), Prince Metternich’s Memoirs (1880), George Standring’s The People’s History of the English Aristocracy (1887), and rereadin

June 15, 1886:   The Clemens family and governess Rosa Hay (a party of six) left Hartford for Elmira and spent the night at the [Sam to Orion June 2] Gedney House at 40th Street and Broadway in New York 

June 19, 1885:  The Clemens family took a special car from New York to Elmira,

June 27, 1885:  In the morning, the Clemens family left Mrs. Langdon’s home for Quarry Farm.