I don't think it's a mistake at all. You got an axle, a frame, a camper body, and whatever is inside. They are just all in the wrong place! Most people spend months or years locating all the different components; you have most of them right here. You just need to disassemble and rearrange! As long as you didn't pay too much, I'd say you have a great project here. I would have bought it for the right price.
One major problem I see [some more pics would be helpful
] is that you don't have much of a turning radius. You need to put some proper drawbars on there that stick out 4 feet or so. You probably want to do that before you move the axle, because it will affect the center of gravity even more.
So how about some more pics! Raise it up and show the inside, I would love to see more...