I believe I have just found Elizabeth Sanders, daughter of Joseph and Martha- not to be confused with Eliza.
I believe that Elizabeth Sanders married George W. Woolman, resided in Otto, Cattaraugus, New York 1840, from there to Michigan.
If this is her, her full name was Elizabeth Susan Sanders. I got her birth record today from the Vermont Archives. Birth date is March 18, 1820. (Also got James birth, the date we have is correct).
Elizabeth Susan Sanders-Woolman died May 12, 1900 Richland, Saginaw, Michigan, USA.
Her death certificate does not list her parents nor her date of birth but everything matches up perfectly otherwise.
I sent in a request today for Ruth Sanders. I am hopeful we can find out where she was born and confirm the birth date I found on the internet and her parents.
Next I will check on Eliza- since we know she was sister to the other Sanders in Erie. I now believe that Joseph and Martha did in fact have two daughters Elizabeth and Eliza. This isn't common, but not unheard of.
Cary