I chose treehouse but in all honesty, I could spend a week straight in any of them. a treehouse would be fine because i'd be away from most of the scary animals that lurke outside in the night and since it's summer time, it would be nice =o) The Tent on the other hand is cool because you are more closed in then you are in a treehouse and theres always the potential to start a small fire and cook up some hot dogs on a stick. Yummmm!!! And the underground buker would just be awesome because there is less of a chance of getting flying insects all up in your business and, i've never done it before so it would just be an interesting experience.