Yes I would use these two expressions interchangeably. In fact just last week I spent 2 nights on an island in Scotland in a small house, in a very small village, at the end of a one-track road which didn't lead anywhere else. Either of these expressions would perfectly describe where I was staying. It was very beautiful there though, and the people were very friendly. 😊

Yes, they are much the same. They both mean in a remote/ far away place, in the middle of nothingness/nowhere. Alice Springs (town) is in the middle of nowhere. Coober Pedy (township) is also in the back of beyond; well a thousand k's north of Adelaide, which might be the same thing to some people. (Adelaide, South Australia = nothingness to some people). Шутка.