*EDITING ORIGINAL REPLY*... I don't have a marriage date or place for Joel & Sarah. (The date I originally posted in case you read this before I had a chance to edit was a possible birth date). My Joseph was born 1804 so I imagine they were married shortly before then.
The only thing, at the moment, that I feel sure of is that I did find a Montgomery, VA marriage record for my Joseph Canterbury that said he was the son of Joel Canterbury.
I also viewed the pension application for my William Canterbury (son of Joseph, grandson of Joel) and found that he was cousin to James L. Canterbury who is the son of Hugh Canterbury. Thus, Hugh and Joseph would be brothers.
There is a Joel Canterbury & Sarah living next to Hugh on the 1850 Gallia Co, OH census. And there is an Isaac Canterbury & Sarah living next to Hugh on the 1860 Gallia Co, OH census.
I have Isaac Joel's kids as being Joseph, James, Nancy, Hugh, Robert, and possibly William. I will have to find my notes though on the connections with James, Nancy, Robert, and William. (Off-hand though, I do know that James' marriage record mentions a Joel Canterbury, there's a Nancy Davis living with Joel on the 1850 census, and a Robert on the 1860 census.)
I have not found a will for Joel in any of the books or records online that I've searched.
*EDITING to ADD* -- If the Joel Canterbury in 1820 & 1830 Giles, Va is in fact "my Joel" (which I think it is), he does appear to have 2 daughters. Nancy fits in for the older daughter (born about 1810). I have no info on who the younger daughter could be other then being born between 1810 & 1820 and most likely married (or died) between 1830 & 1840. There also appears to be at least one son (possibly 2) for this Joel that I do not have a record of...