One recent New York Times discovery is an article dated 15 Apr 1894 listing the Lenox cottages by name with their occupants. It appears that the vast majority came from New York, which may be one reason their social scene was covered as extensively as it was. 
Moving forward, on 2 Aug 1914, the New York Times headlines declared:
“Germany Declares War on Russia, First Shots are Fired;
France is Mobilizing and May Be Drawn in Tomorrow;
Plans to Rescue the 100,000 Americans Now in Europe” 
On that same date, an article was published listing Lenox cottagers currently in Europe, noting that efforts were being made to contact these individuals. Listed among them is my 3rd great aunt, Emily Williams Biddle (1855-1931) and her older brother, Dr. Thomas Biddle (1853-1915). 
A follow-up article dated 14 Aug 1914, notes that the Biddles have decided to “pass the summer in Europe.”  A search of Passenger Lists on Ancestry.com revealed that Thomas and Emily Biddle left Europe in late September, sailing from Liverpool on the Campania, 26 Sept 1914, and arriving back in New York 4 Oct 1914 via Ellis Island. 
Other of my Lenox cottagers ancestors who were in Europe during the summer of 1914 were my great-great grandmother, Adeline Stone Greenleaf (1849-1936) and her son, Richard Cranch Greenleaf (1887-1961). Adeline’s husband, Richard Cranch Greenleaf (b.1845) had died in December of the previous year, 1913. Approximately six months after his death discussions were underway by members of the Lenox Club to purchase the Greenleaf residence, Windyside 
As of 16 Aug 1914, a New York Times article reports that the whereabouts of the Greenleafs in Europe was still unknown, though they were believed to be in the south of France. Apparently Adeline’s signature was needed on documents to complete the sale of Windyside to the Lenox Club.  Passenger lists indicate that Adeline Stone and Richard Cranch Greenleaf left Liverpool on the Finland, 4 Sept 1914, arriving in New York 12 Sept 1914 via Ellis Island. 
 “An Early Season at Lenox; Several New Cottages to be Opened in the Berkshire Hills,” New York Times, 15 Apr 1894. Online : http://query.nytimes.com/gst/abstract.html?res=F10C15FD3D5415738DDDAC0994DC405B8485F0D3. Accessed 12 Oct 2011.
 “First Shots Fired in the Russo-German War.” (1914, August 2). New York Times (1857-1922),p. 1. Retrieved October 12, 2011, from ProQuest Historical Newspapers The New York Times (1851 - 2007). (Document ID: 105456133).
 "Urge Tourists to Leave Europe," New York Times, 2 Aug 1914. Online : http://query.nytimes.com/gst/abstract.html?res=F10F12F8385916738DDDAB0894D0405B848DF1D3. Accessed 12 Oct 2011.
 "Crosby Out of War Zone" New York Times, 14 Aug 1914. Online : http://query.nytimes.com/gst/abstract.html?res=F10910F93A5B13738DDDAD0994D0405B848DF1D3. Accessed 12 Oct 2011.
 “New York Passenger Lists, 1820-1957,” database, Ancestry.com (http://www.ancestry.com : accessed 12 Oct 2011), entry for Emily W Biddle, age 59, arrived 3 Oct 1914 on the Campania.
 Special to The New York Times.. (1914, June 22). MAY COMBINE LENOX CLUBS :Plan Is to Purchase Greenleaf Villa for a Home -- Berkshire Personals.. New York Times (1857-1922),9. Retrieved October 12, 2011, from ProQuest Historical Newspapers The New York Times (1851 - 2007). (Document ID: 100676302).
 "Lenox Gains Through European War," New York Times, 16 Aug 1914. Online : http://query.nytimes.com/gst/abstract.html?res=F5071EF9385916738DDDAF0994D0405B848DF1D3. Accessed 12 Oct 2011.
 “New York Passenger Lists, 1820-1957,” database, Ancestry.com (http://www.ancestry.com : accessed 12 Oct 2011), entry for Adelaide [sic] Emma Greenleaf, age 65, arrived 13 Sept 1914 on the Finland.