Kay, i'd love an underground home. Whenever i get a chance to tour one, I love it. I've seen a few and they are always so calm and cool. I also like the idea of a Hobbit hole. COZY.
It's a good fantasy.
I have a book called something like Build an Underground Home for $50. It was written in the 70s but it has some really good ideas, and plans for expanding from the small space they start you out with.