That is great! There are historians who specialise in Lucy Maud Montgomery, but their availability would depend on their schedules. In consideration of this, one option that I would definitely recommend is the biannual conference that is held here through the L. M. Montgomery Institute in Charlottetown. This year, 2018, happens to be a year when this conference is to be held and is scheduled to include Key Note Speakers Elizabeth Rollins Epperly, Margaret Mackey, Catherine Sheldrick Ross and Emily Woster as well as many other participants. It even includes a pre-conference workshop with Deirdre Kessler whom I once had the honour of participating in her L.M. Montgomery class at the University of Prince Edward Island. The dates for this year's event are scheduled to be June 21-24, 2018.
If you are unable to register for and attend this conference, I would recommend the staff at either the Anne of Green Gables Museum or Lucy Maud's Birthplace as well as the Green Gables Heritage Place. I have often found the staff at each of these locations to be very knowledgeable in things related to L.M. Montgomery' life and works.
I hope that this is helpful. Enjoy learning more about L.M. Montgomery!