HERKIMER COUNTY HEMPSTEADS!

Just found online at familysearch.org some probate documents from Kings County, New York for Christopher Hempstead [Jr.], born approximately 1807, died 1881 in Brooklyn.  The biggest surprise was mention of a deceased son, named - of course - Christopher [III].  He would have been the eldest son, born approximately 1825, married probably Mary [surname unknown], born in Wales.  He married approximately 1850, does not appear in the 1850 census that I can find.  However in the 1860 census there is a Christian Hempstead of the right age, wife born Wales, 3 children that match later details exactly, plus one daughter of whom no further mention is found.  He lived in Erie County, Buffalo, New York.  As far west in the state that you can get.  What could have taken him so far from Brooklyn?  His children later lived in Herkimer County, German Flatts, Ilion township [per 1881 probate documents plus found in earlier censuses].  That's a lot closer to Brooklyn than Erie County, but - how and why did the family, or perhaps orphaned children, remove from Buffalo to Ilion?  In 1870 I found a census entry for the possible widow of Christopher III; few details are shown in that census, but she was still in Buffalo.  Her children in the same census year were mostly in Herkimer County, living in various households.   Only one child, daughter Phoebe E. Hempstead, was living in Brooklyn at the date of Christopher Hempstead [Jr.]'s probate; she was of full age and residing in an orphan asylum.  She was found at the same approximate address at the 1880 census.  Had she lived there long?  How did she get back to Brooklyn?