Hi Mac,
Very good question.
His section in "The Irish Aboard Titanic" by Senan Molony provides a little more detail. It is stated that he had been visiting friends in Ireland during a sabbatical from his pastoral work.
"Records of lawsuits against the White Star Line show that the Revd. Kirkland had family members living in Old Town, Maine. He had six childern, named as sons Algie, Henry, Allen, and daughters Alma Jipson, Myrte Treadwell and Maude Elden".
Regarding his onboard actions. Evidently, Kirkland was one of the more elusive 2nd class passengers who kept a very low profile. However, it seems a possibility that he was the "man from Edinburgh" whom Mrs. James Watt referred to as having informed her of the collision with the iceberg.
As the only Scotsmen in 2nd class were Kirkland and Robert Douglas Norman, we can assume that the "Edinburgh" man must be one of them. Both men were, in fact, from Glasgow, but Mrs. Watt may have been mistaken.
I have sent e-mails to two descendants of this man, but both addresses appear to have expired as both were sent back to me! I will keep trying.
Hope this helps,
Ben