William was a member of the Baptist Church at Providence. His gravestone is pictured at findagrave.com
From RI Genealogical Register Vol 13 p 103: the will of William Potter, of Pr, joyner, was dated 7 Nov 1729, proved 1 Dec 1729. It mentions wife Martha, bro-in-law Chrales Tillinghast who is co-ex with wife, bro John Potter, son William who is under 21, and dtrs all under 21 Amey, Ruth, Martha, & Sarah.
The full details of William's will can be found in The Tillinghasts in America, First Four Generations, p 105, by Wayne G. Tillinghast, 2006, RI Genealogical Society.