July 6 - July 29, 1868:  Return to New York.  Departed San Francisco aboard the Montana.  July 11 at 12:30 am, Cabo San Lucas.  Twain arrived in New York July 29, 1868.
Cabo San Lucas - July 11
Acapulco - July 13
Panama City - July 20:  Met with Ned Wakeman
Aspinall - Boarded the Henry Chauncey
Arrived in New York July 29 and checked into the Westminster Hotel.  Mark Twain would never again return to California or Nevada.
August 4: Hartford

From page 470 The Life of Mark Twain: The Early Years, 1835-1871:

Sam sailed the next day aboard the steamer Montana with 150 other passengers, paused on July 13 in Acapulco and on July 20 in Panama City, where he crossed paths with his friend Ned Wakeman, “as tempestuous of exterior, as hearty of manner and as stormy of voice as ever,—and just as good a man as exists anywhere.’ Wakeman told him a fantastic dream tale about “a visit which he had made to heaven. I kept it in my mind, and a month or two later I put it on paper. ... 

He finally published part of the manuscript in Harper’ Monthly under the title “Extract from Captain Stormfield’s Visit to Heaven” (1907-8), about a journey to the celestial realm. A revised version appeared in book form in 1909 and was the last story Sam published before his death. ...

The day after Sam heard Wakeman relate the story about his visit to heaven, he crossed the isthmus by train, caught the Henry Chauncey at Aspinwall, reached New York on July 28, registered at the Westminster Hotel, and entrained on August 4 to Hartford to deliver his book manuscript to Bliss. He never set foot in California or Nevada again. 

From Lorch: "...Hartford, Connecticut, to talk with Elisha Bliss about his forthcoming book, Innocents Abroad.  There was still work to do on the manuscript, and since Bliss hoped to bring the book out in December, he remained in Hartford to finish it. ...But his primary concerns during the weeks that followed were the courtship of Olivia Langdon of Elmira, New York, and the growing necessity of replenishing his rapidly diminishing funds." (pg.87)