Jaeger,
Monetti's "History of the Sands Point Golf Club" was a good effort but incomplete. Some of the Club's history can be found in an article in the latest Met Golfer magazine.
http://www.metgolferdigital.com/i/599592-nov-dec-2015Sands Point Golf Club was founded in 1898 and had a 9-hole course in the "Roslyn Hills." It was 2,109 yards in length. It would be sold at a foreclosure sale to Harry Tibbits in 1914. They eventually would lease property on the estate of S.I. Van Wart. After his passing this property would be sold at auction on the same day as the estate of Julius Fleischman that had the 9-hole Harbor Hills Country Club course. Both of these properties would be purchased by the founders of Sands Point Golf Club.
After Tilly first looked at the property he wrote a letter dated 4/3/1927 which is also contained in the Monetti article. According to Monetti, Tilly was asked to "revamp the first 9 holes [Harbor Hills] and complete the second 9 [Sands Point]..." In Tilly's letter he tells the club that the present golf course measured 5,375 yards and that many of the holes were generally mediocre. He stated "Is the property worthy of a modern course? Most assuredly. Is the present plan good? No, it is very bad."
Tilly would use a number of the Harbor Hills holes and a handful only of the Sands Point holes throughout the new design, each of which were changed to fit into the entire new course he created.
As the Guggenheims and their private estate courses have been mentioned throughout this thread, it is of interest that Harry Guggenheim was on the original board of Sands Point.