Mark,
Because of the austere financial situation at the park which was brought about by WW II and the drastic reduction in rounds played due to so many young men joining the military, the condition and even the architecture of all 4 of the courses park would greatly suffer for many, many decades into the future. It became most serious in 1942 when the State closed down the Blue & Black courses for the duration of the war, not even cutting the grass until they decided to re-open them after peace was reached in 1945. As a result, many mowing patterns which had been adopted as a means of budget savings were continued. This included a drastic reduction in the sizes of all the greens. Take a careful look at the size of the putting surfaces on the Red in the aerial, especially comparing how tight the bunkers were to them, and you can appreciate just how much those maintenance practices shrunk the greens. Even today the putting surfaces in relation to the bunkers on the Red course are still too far away and the greens need expanding. There are also bunkers that are completely ‘rough-locked’ and which were originally at least partly in the fairways.
With that context established, and before answering your questions, consider the actual plan of development for the park and its golf courses:
You have 3 questions:
1. Was there a tee back in the corner of the trees, to the side of the 12th green?
2. Did the hole play out left to a shared fairway with 11?
3. Did the current right side fairway only come about after trees were added down the left?
To best answer that question take a look at a close-up of the original design of the hole as shown on the development plan:
As you can see the hole was never designed to have to fairways split by a central large hazard. In fact, there were originally two large hazards which were typical of what we find designed and built throughout all of the 4 courses. You can also see, in answer to your 2nd question, that there was a rather large area of rough which separated the 11th & 13th fairways and that they were separate and distinct from each other.
There were 2 tee boxes including one that was much closer to the green and a bit further back than the one that is used today. What few realize though is that Tilly designed the hole with the idea of having the better player challenge both hazards in order to have the best angle of play into the green. Note the line of play that he drew in and how shots from both tees would have to either carry or skirt the edge of the left bunker complex to find the preferred landing area. Also, note that the lesser player who would play to the larger and more open section on the right side of the fairway would many times mean a lay-up short of the green for the 2nd shot as they wouldn’t want to challenge the right green-side bunker. The large second hazard would also challenge the long-driver off the tee.
Further careful examining of that larger second hazard and one can see an almost Reef-like/Hell’s Half-Acre design amalgamation to it in the way it angles from lower right to upper left sides of the fairway and in its size.
Yes, in answer to your 3rd question, the right side was expanded after the trees were planted in the left rough to serve as a safety feature for wayward tee shots that were finding their way onto the 11th fairway and into those playing that hole.
One other very important point which was not mentioned. This photograph can be found on the Vanderbilt Cup Races blog created by Town of North Hempstead Historian, Howard Kroplick. The website can be seen here:
http://www.vanderbiltcupraces.com/ Also on this site you'll see that this isn't the only Bethpage aerial and that there are aerials of other New York City/Long Island golf courses including Tilly's Fresh Meadows which was his first design to host two major championships and that is no longer in existence. In addition, Long Islander Phil Carlucci, who is currently working on a coffee table book about Long island golf courses which should be out next spring, shared this photo with me and asked me for information about what it was actually showing and how to date it.