James,
A brief article I saw on underground homeless camp in Kansas: Underground homeless camp cleared near the East Bottoms [1].
Although the article does not give much detail, I find it an interesting use of space, staying out of the way and a lesson to learn regarding people who may be close to your proximity without one even knowing it. It also drew my mind back to the Bielski partisans [2] and the camps they dug in Naliboki Forest.
God Bless, – John in Ohio