I was going through a couple of Don’s notebooks and stumbled on this page (click on the image for an enlargement). He lists his August 1979 meetings for on-going projects with Dr. Koop (Clover Hills Drive) on August 8 with the Spencers (240 Allens Creek Rd.) on August 6, with the Crookshanks (1122 East Lake Rd. Canandaigua) on the 14th and later that day with Dr. Koop. And then August 17… his stroke.
It looks like he took some time off and then jumped back into his projects. The following list is dated 2/10/1981 and enumerates aspects of the Crookshank project on Canandaigua Lake, his last full home project.