"Considering that many of the Gulph Mills members came from Merion and other well-known clubs, why did they choose Ross to design their course? Was Flynn or McRaynor not available?"
Brian:
Although GMGC has all the minutes of all the board meetings of the club since it was formed in 1916 I'm not sure why the club hired Ross and not Flynn or Macdonald/Raynor or someone else. The club was actually formed in Sept. 1916. The first organizational meeting was held in June 1916 and a letter from Weston Hibbs who in a sense was our founding member who oversaw the entire construction of the golf course states that that he spent three days with Ross going over the property in the middle of July 1916. As to why they hired Ross, though, I can't say.
In 1916 Flynn actually was a practicing (and advertizing) professional architect and had already begun work on a few golf courses (Doylestown and Harrisburg) on his own. However, seeing as the founding members of GMGC seem to have been a group of about 10-11 disaffected members from Merion Cricket Club due to overcrowded golf there it may've been that they weren't willing to use someone from Merion at that point. Ross, even at that time was one of the better known PROFESSIONAL golf architects of which there still were not that many. Most of the best known Philadelphia architects at that time were the "amateurs"---eg Crump, Wilson, Thomas who would not take a fee for their services. Tillinghast was here and had become a professional but apparently Ross was better known at that time.
Coincidentally, even though I've never been too sure of the circumstances (Pete Trenham might know), it may've had something to do with my own grandfather, A.J. Drexel Paul. The reason I say that is St. David's G.C., a club he was very closely connected to also hired Ross about ten years later.
St. David's G.C. was in another location than it is now, and it seems Paul was a member of that club too (so was George Crump). St. David's wanted to move their club and it seems they were depending on Paul to help them do that. However, he and a group of his friends started GMGC instead. But then later St. David's did move to their present location which is on land that Paul sold them (the Pauls still live right next to St. David's G.C.). So I don't know whether it was a coincidence that both GMGC and St David's hired Ross to design their courses but considering Paul's close involvement in both those Ross courses perhaps he had something to do with the hiring of Ross.
I don't know much about this but my own father who at the time was about 6-10 years old was put in school in Aiken S.C. where his parents spent some time in the winter so perhaps they may've been quite familiar with Pinehurst where obviously Ross was based.
Obviously back then the town was pretty small and those in golf, and even in business all seem to have known each other. I recently found out that Drexel & Co. which was at that time a big player in the financial world was run by my own great grandfather, James W. Paul (he married one of founder A.J. Drexel's daughters) and one of the operating partners of Drexel & Co. at that time was George Thomas's father.
John Ott, of PVGC, once said that the key to understanding the "Philadelphia School" of golf architecture was understanding how close they all were---that basically back then they were all close friends and golfing partners.
But apparently with both GMGC and St David's they wanted someone who was clearly a professional and perhaps from outside the area too---and that was Ross.
That's my supposition but I sure can't prove it.