Have you sent for CW records? Will cost $10, but MIGHT have some info on the
family, ask for the Pension Records, and perhaps where buried and exact date
of death if you don't have that. This might lead to an obit, or cemetery
records. I'd try the Surrogate Court for the County Buffalo is in (mental
blank!) just in case John left a will and died in that county. It sounds
like they moved out of Buffalo, but may have remained in the area. Check for
your g'g'ma in the 1860 census, now indexed.
Hope this helps a bit.
Eltiemblo