Hi Dan,
Do you think your Buchanans are connected to George Buchanan who had a farm on Buchanan's Mountain, Middle River, Cape Breton? His daughter Lillias was married to Norman McMillan who apparently came from Lewis, as did many of their neighbours. Norman McMillan had the adjoining farm and later acquired the Buchanan farm. The area is now known as MacMillan's Mountain. Norman and Lillias were my gg grandparents.
Thanks, Lindsay (McMillan) Michie