You'll be glad to know there is much more to Rathmullen than just land and a house...
Rathmullen, Ballymote, Co. Sligo had its own school, so you will be able to read through delightful local history tales recorded by Rathmullen schoolchildren in 1939.
From this you can see that Ballymote Castle was an important landmark and a source of pride. Check out the famous late-medieval Irish manuscript known as The Book of Ballymote. See also Caves of Keash. Ballymote, albeit small mid-Sligo town, has a rich heritage as a 'Gaelic Centre'.
Comparing Rathmullen's historic maps (6 inch and 25 inch), you can see that the position of Rathmullen's original school house (townland of Ardree, par. EMLAGHFAD) was cleared to make way for the Dublin-Sligo railway (planned 1853, open 1862). Rathmullen National School was relocated near the Big Bridge (townland of Carrickrathmullin, par. DRUMRAT). These maps also reveal that Owenmore River caused much of Rathmullen to be liable to flooding.
Rathmullen's primary landlords were Sir Robert Gore Booth of Lissadell House, and William Phibbs (1803-1881) of Seafield. Both were known for their cruelty to tenants, and much has been written about them. You may find Rathmullen or your family mentioned in these landlords' estate records or history books.
At the time of Griffith's Valuation, Rathmullen village centred around the crossroads in the townland of Ardree. It had its own bakery ... Mr James Lowther (a baker with 10 children to support) lost his entire Rathmullen premises to a fire there in 1856. That same year, it was also a source of scandal ... Michael Doudney of Rathmullen, after night of drinking at Healy's house, got into a fight with Michael Keane and received a fatal blow of a loy to the head. (Keane was found guilty of manslaughter and convicted for 18 months).
See also Ballymote Emlaghfad Cemetery
To build your story around Rathmullen, you will also find it helpful to link in with The Ballymote Heritage Group. (They are very active and publish The Corran Herald annually, chock full of local area and family history).
Best of luck!