"Six months after my entry into journalism the grand “flush times” of Silverland began, and they continued with unabated splendor for three years. All difficulty about filling up the “local department” ceased, and the only trouble now was how to make the lengthened columns hold the world of incidents and happenings that came to our literary net every day. Virginia had grown to be the “livest” town, for its age and population, that America had ever produced. The sidewalks swarmed with people—to such an extent, indeed, that it was generally no easy matter to stem the human tide. The streets themselves were just as crowded with quartz wagons, freight teams and other vehicles. The procession was endless. So great was the pack, that buggies frequently had to wait half an hour for an opportunity to cross the principal street. Joy sat on every countenance, and there was a glad, almost fierce, intensity in every eye, that told of the money-getting schemes that were seething in every brain and the high hope that held sway in every heart. Money was as plenty as dust; every individual considered himself wealthy, and a melancholy countenance was nowhere to be seen. There were military companies, fire companies, brass bands, banks, hotels, theatres, “hurdy- gurdy houses,” wide-open gambling palaces, political pow-wows, civic processions, street fights, murders, inquests, riots, a whiskey mill every fifteen steps, a Board of Aldermen, a Mayor, a City Surveyor, a City Engineer, a Chief of the Fire Department, with First, Second and Third Assistants, a Chief of Police, City Marshal and a large police force, two Boards of Mining Brokers, a dozen breweries and half a dozen jails and station-houses in full operation, and some talk of building a church. The “flush times” were in magnificent flower! Large fire-proof brick buildings were going up in the principal streets, and the wooden suburbs were spreading out in all directions. Town lots soared up to prices that were amazing.
The great “Comstock lode” stretched its opulent length straight through the town from north to south, and every mine on it was in diligent process of development. One of these mines alone employed six hundred and seventy-five men, and in the matter of elections the adage was, “as the ‘Gould and Curry’ goes, so goes the city.” Laboring men’s wages were four and six dollars a day, and they worked in three “shifts” or gangs, and the blasting and picking and shoveling went on without ceasing, night and day." (Roughing It)

From May to July of 1863, Sam was in San Francisco.  In July, his boarding house burnt down and he reportedly caught a cold.  Scharnhorst theorizes that Sam may have been suffering from a venereal disease.  The traveled to Steamboat Springs for a cure.

Sam was soon dressing in motley and moved alone to a room in a mansion on A Street. He re-created the fire in chapter 7 of The American Claimant thirty years later.

From  The Life of Mark Twain: The Early Years, 1835-1871, page 204

Sam apparently fell ill after he was dispossessed. “On the day of the fire, my constitution succumbed to a severe cold caused by undue exertion in getting ready to do something,” he reported, and he left Virginia City on August 11 with Adair Wilson of the Union (aka the Unimportant) to recuperate for two weeks in Steamboat Springs, named for the vapor that wafted above the resort near Lake Tahoe. “Those two pilfering reporters,” carped the Virginia Evening Bulletin, “will no doubt bore the sojourners at that retreat with some of their infernally disgusting ‘platitudes.’”

...

In a letter to the Morning Call dated August 20, Sam explained how he “carried over to the lake a heavy cold, and acted so imprudently during a week, that it constantly grew heavier and heavier—until at last it came near outweighing me.” Still suffering from his cold, he returned to Virginia City on August 23. When Dan De Quille returned from the East on September 5 to resume his duties at the Enterprise, Sam was free to return to Steamboat Springs. In his essay “How to Cure a Cold” (1863) he described traveling by Stage from Virginia City to recuperate. At the Lake House, an “excellent hotel” at a “beautiful and picturesque point” on the east shore of Tahoe, according to J. Ross Browne, Sam experimented with an allopathic remedy, a homemade tonic called Wake-Up Jake, like those his mother sometimes administered, which consisted of “warm salt-water, solution of molasses, aquafortis, and turpentine, and various other drugs.” The repulsive concoction tasted as “if I had swallowed a slaughter-house” and robbed him “of all moral principle.” He also tried a concoction of gin and onions, which gave him “breath like a buzzard’s.” He finally traveled to San Francisco and registered at the Lick House, where “a lady ... told me to drink a quart of whisky every twenty-four hours, and a friend at the Occidental recommended precisely the same course. Each advised me to take a quart—that makes half a gallon.” “How to Cure a Cold” became one of Sam's most successful apprenticeship pieces. It was the earliest of his writings to be reprinted in his first collection of humorous articles in 1867, and it was the earlies of his articles to appear in his collection Sketches New and Old (1875).

Sam was in Virginia City on the 5th of September but departed on the Carpenter & Hoog Stage to Carson, departed Carson City on the Pioneer Stage, September 6th, arriving in Sacramento on the 7th and San Francisco on the 8th, registering at the Lick House.  He departed San Francisco, returning to Carson City October 10th.  Back in Nevada, Sam alternated between Virginia City and Carson City several times with side trips to Como, Nevada and Silver Mountain.

Artemus Ward was in Virginia City from December 18 to the 29th.  The Sanitary Fund Flour Sack Promotion began April 19th and was significant in Sam's departure of Virginia City and relocation to San Francisco May 29th, 1864.