And, if you can get 30 or 40 friends with muscle and enthusiasm, you can carry it bodily to its new home. I saw this done in Korea many years ago when several hundred men surrounded a Quonset hut, picked it up at the command of a honcho, and, chanting as they heaved, trotted off with it to its new site. An important part of moving a building this way is to make sure the carriers have handles to grab, not the bottom of the building. If all this doesn't seem practical, consider taking off the roof so you can move the body and the roof separately. Q. I built a shed in the back yard to store a snowblower.
Trouble is, the plywood floor gets very wet, and that is no good.
If the floor is exterior plywood, it will resist water for some years, especially if the floor dries out reasonably fast after getting wet. Q. A small guest house was on my property when I bought it. The wood walls are too close to the ground. The floorboards are crumbling badly. From your description, it does not sound like bugs, but rather decay from moisture and a fungus.