Glen,
The last original design(s) by Tilly was the single largest golf course complex ever built then or since. The three courses at Bethpage State Park, the Reb, Blue and Black courses. There has never been another example where three courses were planned and built all at the SAME time. Places such as Pinehurst and Bandon and the huge complex of 10 courses (and growing) outside of Beijing are larger, but at not time were three courses or more built and designed at a single time.
All three were scheduled for a 1935 opening, but weather problems forced the seeding of the Black to be delayed until the spring of 1935 and so it didn't open for play in 1935 as the other two did.
There were two unintended consequences as a result. First, the 1936 Public Links Championship which had been awarded to Bethpage with the idea that it would be contested on the Black and Red courses would now be contested on the Red and Blue.
The second is that with the Black's hosting of the U.S. Open championship in 2002, Bethpage is the only golf club that can lay claim to THREE different courses hosting a national championship.
After tilly finished his PGA Course Consultation tour in August of 1937 he joined forces with billy Bell, but their work was limited by the Depression. Both Brookside and Virginia were major renovations projects and as such can not be considered original designs.
The very last original design that has ever been mentioned (this in an article in the Pacific Golfer by Tilly) was a reference to a new course design in Seattle that he and Bell were planning.
No one has ever been able to find anything else concerning this project, not even location for it.
Maybe there is a missing Tilly/Bell somewhere out there that Jordan or others have walked un unawares...