John,
We located a very large collection of Flynn's drawings that were stored in a box in the barn of Flynn's construction associate, William Gordon and thus came into ownership by his son, David. This included over 80 sets of drawings (routing maps, topos and in many cases complete sets of hole drawings) representing the length and depth of the country from Shinnecock to Cherry Hills and The Country Club to Indian Creek. We've since added nearly 40 other drawings to the collection, some from clubs that weren't in the Gordon box so that the complete collection represents everything Flynn did after 1919 (I guess earlier work was not retained). By the way, we have 12 of the 18 hole drawings built as planned for Kittansett proving the routing and design is Flynn. In many cases drawings of existing layouts that Flynn would redesign are in the collection as well enabling us to know what was there prior to Flynn and therefore what Flynn did. We know what Flynn did at Merion, Shinnecock, TCC and other places. In every case it was much greater than previously thought. In the case of Shinnecock, the entire course is Flynn--every tee, bunker and green (with the possible exception of the 3rd green).
The drawings answered so many questions that our book project went from pamphlet to 3-volumes over the course of a six year period.