Neil and Joe:
The Mackenzie/Maxwell connection and certainly the Mackenzie/Maxwell connection in Philadelphia seems to be a pretty sketchy one at this point but by that I sure don't mean it isn't a fascinating one and a very interesting one to research further and deeper.
In my opinion, Maxwell's connection to Philadelphia architecture is just as interesting and probably more so than the Mackenzie/Maxwell connection at Melrose GC.
It seems that Maxwell's initial connection and design in Philadelephia was the NLE Pennsylvania GC in Llanerch, a course that did not last very long as its club moved to Malvern to what is now Chester Valley GC (which Maxwell supposedly had a good deal to do with too). On neither of those projects did Maxwell partner with Mackenzie, though----at least I don't believe he did.
But back to the question of how Oklahoman Maxwell established the architectural connection he did in the general Philaledphia area which in the end was as impressive for his redesign work in this area as for new construction.
It is pure speculation on my part at this point, but something tells me Maxwell was introduced to Philadelphia by the extremely powerful railroad contingent in this town. That contingent was always deeply entrenched in MCC (basically Merion) through the likes of Morgan and Drexel financing companies and the men from Merion who were partners of those companies or the basic investors in them as they basically controlled the financing of a number of American railroads most certainly including The Pennsylvania RR and the powerful Reading RR.
But the key may be how those RR magnates and their financial RR interests may've gone much farther and wider around the country and basically national. I'm talking about men seminal to the Merion move to Ardmore such as Horatio Gates Lloyd and Rodman Griscom and a number of others at MCC who were really powerful with American RR financing and on the boards of numerous American RRs.
The key player just may be a man who has been little heard of on these threads by the name of T. DeWitt Cuyler. He was basically the most powerful man in the teens and early 1920s in the American RR system. He was the chairman of what was known as the Association of American RR Executives and it seems his mission was to attempt to take the American RRs back toward privatization and nationally.
I belive he died in something like 1922 but essentially this RR structure was set and its influence could be felt through some of these clubs and projects, certainly MCC's and seemingly Maxwell's first project in Philadelphia----eg The Pennsylvania GC, a club that was seemingly built or owned by the Pennsylvania RR.
T. DeWitt Cuyler, by the way, was also MCC's lawyer in 1910 and 1911 and was the one who essentially set up its complex financial structure giving Horatio Gates Lloyd total control over the land that would be bought from the real estate developers and turned into Merion East golf course and club in 1911 through the vehicle of the Merion Cricket Club Golf Association that owned the land and leased in back to MCC.
For about eight months from Dec 1910 until July 1911 Horatio Gates Lloyd (and his wife) would own all of what became Merion Ardmore. The reason for that is so he could freely alter boundaries between the real estate development (which he controlled) and the golf course plans.
This is why that committee engineer, Richard Francis, went to see him in the middle of the night to fix the problem of the routing on #15 and #16.
The whole thing was preconceived and apparently by both Lloyd and Cuyler in late 1910 (at which point the MCC president signed off on it). The fact that they were hugely powerful with American RRs might be a connection to Maxwell, as Cuyler was on more than half the boards of the entire American RR system and traveled the nation in that vein. Being a golfer perhaps he is the one who ran across Maxwell in his early days in Oklahoma as he knew and dealt with some pretty poweful people out there who were probably in the RR business or using them massively in their related businesses such as oil and even salt.
If that's how Maxwell first was introduced to Philadelphia golf and architecture it makes a lot of sense because those men who were so powerful in the American RR system were massively well connected through the prominent clubs of that time such as PCC, MCC, PVGC etc, etc.
And that was just Philadelphia. Maxwell seemed to be commensurately well connected architecturally in and around New York and particularly Long Island. That could be explained by his friendship with J.P. Morgan II, a man whose company was the primary financier of this entire American RR system through Philadelaphia and around the country---eg read the fascinating financing and business wars of Morgan against other competing business interests over the northern North American line knowns as the Northern Pacific RR.
This remarkable group of men from these various cities all seemed to know each other well and so many of them and their close friends were the founders and principles behind so many of these famous early golf clubs including NGLA, MCC, Maidstone, Shinnecock, The Creek, The Links, Lido, etc, etc.
The likes of Morgan (both father and son) were certainly rich but more than that they were so powerful throught the interconnected world of the American RRs, American shipping, in some cases the incipient American aviation industry (Shinnecock's Juan Tripp) and also some of the type flight golf courses of that early time.
Apparently most all of them really liked the likes of Perry Maxwell and also William Flynn!
And not just that but I don't think any of us can deny that in a business context the burgeoning American RR system and the burgeoning golf industry basically went hand in hand throughout for obvious reasons. Together they were a total "win/win" deal, one for the other!