Oh, then we are looking at this William Walker from a very similar angle. Well, I have heard that he was baptized at Dunkineely Methodist Church. I do not have the date of his taking ship for America, but he married Grace in July 1900 in New York. Decades after William's death, his earthly remains were disinterred in preparation for creation of the Cannonsville Reservoir. I believe they were reinterred in Delhi, NY.
On a broader note, your grandfather, Gerald Walker, stated during his lifetime that his family hailed originally from Wales. Gerald's daughter, Virginia, related this years back. This would have differentiated William Walker's family from other Walkers in Donegal. I have no idea, though, the length of the residence in Donegal after leaving Wales. Had you also heard this part about Wales?