Technically, this story is taking place in the canon Supernatural world, so the little burrow wouldn’t exist. However, if anyone has any headcanons for them or ideas, feel free >w> I love coming up with things.
As for sheer immensity, it would be impossible for any interactions between such a difference unless a normal sized human played middleman. They’d have to choose between their love of freedom and their safety if it came down to the choice to leave the burrow behind.
Brothers Apart 