In historic fiction, places and time spans might not be strictly correct, but most people who write in that genre attempt to have some sense of geography. The home of the Taka clan is a mythical province called Great Bay. As a novel of fiction, but based on a historic person and historic setting, this device allows enough artistic license for the Sword of the Taka Samurai to hopefully not become too didactic. I had thought the location would not play a big role in the first book of the series, Cold Blood, but I was wrong. I was almost immediately asked to provide a map. Here goes: Great Bay Prefecture takes the western part of Kagoshima in the south of present day Kyushu and is combined with the south western part--about half--of present day Miyazaki.
Long Sword would be from present day Oita.
Kita, where she stays at the Wakatake Inn is in Fukuoka Prefecture. The Kanmon Strait is there.
The second part of Cold Blood and most of Cold Heart takes place in Nagato located within present day Yamaguchi on Honshu, the Main Isle.
The straight line distance from the Taka compound near Cape Toi to the Kanmon Strait is about 150 miles, which takes her about 10 days.
(above) Kyushu today. In Yamabuki's time it was called the Isle of Unknown Fire.
(above) As seen today, the area in and around the mythical Taka compound.