I have found some more information about Luther and family that came to Watertown, Wisconsin. It is not complete, but I've found more recently.
Luther Schermerhorn b. 1798 and Jane Simpson (came to Jefferson, County, Wisconsin in 1844, statehood in 1848)
they both appeared to have died after they came to Wisconsin but have not yet found exactly where they died or if they had a marked burial.
Elizabeth Schermerhorn b 1825 and John Perry b 1815 (came to Jefferson, County, Wisconsin in 1844, statehood in 1848)
I found more info recently in Elizabeth Schermerhorn and John Perry's obituaries in the Dodge/Jefferson Counties Genealogical Society Library.
Hope this is helpful