Moving farther downtown, we can duck into the Duane Reade pharmacy at the corner of Park Avenue and Thirty-Fourth Street to buy a Vitamin Water and try to imagine when this was the lobby and bar of Alfred’s tony Vanderbilt Hotel, designed for wealthy young playboys like him to live sumptuously and well without all the fuss of keeping a house. Alfred took the top two stories for his own aerie when the hotel opened in 1912, but he barely had any time to enjoy it before he went down on the R.M.S. Lusitania in 1915.