Question about what you are hoping to achieve. Is the end goal to see the design and the terrain model positioned on a map that extends outside the project site OR to just make sure the design is positioned correctly on the site terrain you created?
If the later, are any of your initial survey points discoverable on the real-world project site?
If you have 2 points, they could be used to designate the origin (0,0,0) and the direction of the X-axis from which the design would be positioned.
Once you have this set in the model, you can accurately position the design based on the X,Y,Z coordinates relative to the designated project origin
CD