I'm guessing National Parks are a no, but just government owned land - I'm talking like miles from even a road. I'm pretty sure if you did it in the right place, no one would even notice. I'm envisioning something similar to the TV show Alone, a primitive shelter, but no restrictions on supplies, and in a location with a nicer climate. If you know what you are doing, I'm sure it would be pretty easy, but would it be legal?