At age 31, he was killed in action at Guadalcanal on October 15, 1943.
Mrs MacDonald learned early on that her father was buried in a cemetery in Bourail, New Caledonia, but other details about his life remained hard to come by.
She sought more information about her dad through relatives, including Mr Finlayson's younger brother - but he died while writing a story about him for her.
And despite wanting to visit New Caledonia to see her father's resting place, spare money was always used to visit grandchildren who lived in Australia and Malaysia.
But earlier this year, Mrs MacDonald's husband, Peter, entered a New Caledonia Tourism competition with the express purpose of getting his wife to the island.
Mrs MacDonald couldn't believe it when they won the three-day trip. They will visit the island early next month.
"When we won the trip, I was very emotional. I have always felt there's been a link missing in my life. I have dearly wanted to visit him to be close to him, that's all."