I just noticed this morning that one of the graphics entitled "The Golden City in Revelation" shows the size of the New jerusalem overlaid on a map of the United States. My suggestion would be to do the same thing, but have it overlaid on a map of the Middle East/Europe area, since Jerusalem (as we know it today) is located in that part of the world. This would also help those who live in another part of the world, besides the U.S., to get a better concept of the size.
Thanks!