David,
Those are good questions, and your line does represent what I think is the clearing line on 4. I don't know how well you read the topos, but if you look at the topo on the stick routing, you will see no. 4 dogleg at the crest of the hill. You will also note that in that area, 4 only has one contour line across - about 5 feet. Just right of the fw, contours bunch together closer, indicating a steeper slope, which eventually was used for housing.
In the Brown photo, the top gets steeper just right of the sandy road, just as indicated on the stick routing topo. This leads me to believe that sandy road is the right edge of 4 FW and the same basic alignment as used later. If 3 and 4 were both left of that, then it goes from looking too wide to looking too narrow, at least to my eye.
On the other hand, at one point, Patrick reported that the entire area was cleared, leaving no trees between holes as would be common. Perhaps he could chime in as to whether he knows that from another source, or he presumed that from his take on this very photo. Actually, the thing that would make your interpretation make sense is the fact that I don't think that housing was contemplated at that early point, but merely fit in later. And to this day, you can see a caddie path between 3 and 4 on Google photos, which might be what that sandy path turned into, rather than a housing road.
As I said, what works against that theory is that I don't see any steep natural up slope to the left of No. 4 fw in the LZ on the stick topo, which was hand surveyed and presumably pretty accurate. It appears to me that there is a little slope down to the right from that sandy lane, although perhaps the bushes play tricks on the eyes.