This seems to be something people don’t always give second thought to. When people talk about the homeless, the first things thought about are images of people on busy city streets in rusty clothes waiting around near allies. In there, the answer is quite static, because it can be I guess. But if that’s the case, change the setting and that changes too. In the places where I’ve lived, people often needed that mapped out. Where are they known in your rural locales?
Abandoned homesteads, village homes or dachas. Some areas have a lot of abandoned houses. It sometimes takes years to find squatters in some places. My father in law is an alcoholic who has been moving between abandoned houses for 5 years now, sometimes with owner’s permission.
Near bigger cities, you sometimes get forest camps, but local government tends to remove them when they are found.