Hopefully at least one of John and Mary's children's death certificates and obituaries would have her maiden name.
John's death may have also been recorded at the Cumberland County Register of Wills. It may not tell you much more than the Alms House record except where he was buried. Deeds at the Cumberland County Recorder of Deeds may have helpful data, but they won't do the research. You have to do itself or hire someone.
I won't restrict your search for a John M. Good. He may appear in a number of records without the middle initial.
The close proximity to York County may mean they went to a church in that county. Check with the York County Heritage Center to see if they have anything.