McCabe & Duffy of Killyliss, Cormeen, (parish of Aghnamullen), Monaghan

My maternal grandfather, Terence McCabe was born in 1875 in Killyliss, Cormeen Monaghan, he died in England in 1945. He was the son of Michael McCabe, a small farmer and Susan Duffy (maiden name). My mother visited her fathers home in about 1965 when some cousins, Thomas and Delia McCabe were still living in or near the old farm at Killyliss. The family were Roman Catholic. They continued to keep in contact for a number of years until they passed away; my mother has also passed now too. I have been researching my family history for several years and have found it difficult to trace the family beyond Michael & Susan, finally exhausting those records that are available online (Ancestry, FMP, Griffiths Valuation, 1901, 1911 census, baptism and civil records. Although I believe from one record (from 1858 Griffiths Valuation) another Terence McCabe might be Michaels father. Can anyone give me any guidance as to where I can find any additional archive material in Co Monaghan that may be of use, that is not already on-line? I am also looking to make contact with anyone has any knowledge of this family or their descendents. I will be visiting Co Monaghan in June to hopefully identify exactly where they were born, lived and died. Any help or advice would be appreciated.

Terence Murfitt