Click for view from right here

Brown: Marion's Royal Arthur School; dark blue: Edith's rooms; green: Marion's rooms; green X: Hugh's rooms; light blue: Dominion Square; yellow: Flo's William Lunn School. Purple: McGill, leading to Lorne and in the McGill Ghetto. Bleury address, where she stayed at the McCoys, is plunk in the middle of tourist district in Old Montreal. It would be east and south from Dominion Square a bit. It's a parking lot.