The conveyance is in King George County Deed Book 2, beginning on p. 220, November 2 and 3, 1738. These were deeds of lease and release from John Grant and Margaret Grant, his wife, executrix of the last will and testament of William Strother deceased, to Augustine Washington, for 280 acres.
I used to have a photocopy of the deeds of lease and release, but can't find them. If I do locate them I'll post the text. But you might just want to write to the Clerk of the King George County Circuit Court and obtain copies.
The deed does say that Strother obtained the property in separate conveyances from Alice Cale, Thomas Harwood, and John Hartshorn, and that they adjoined. However, the conveyances from Harwood and Hartshorn describe the very same tract of land (150 acres) rather than adjoining tracts. And the 165 acres that Alice Cale sold to William Strother did not adjoin the Harwood/Hartshorn section (which is where William Strother built his house). It was separated from the main tract by land eventually owned by Anthony Strother. Augustine Washington's executors eventually sold the Cale tract to Anthony Strother.