A [right circular cone](https://artofproblemsolving.com/wiki/index.php/Right_cone) has a [base](https://artofproblemsolving.com/wiki/index.php/Base) with [radius](https://artofproblemsolving.com/wiki/index.php/Radius) $600$ and [height](https://artofproblemsolving.com/wiki/index.php/Height) $200\sqrt{7}.$ A fly starts at a point on the surface of the cone whose distance from the [vertex](https://artofproblemsolving.com/wiki/index.php/Vertex) of the cone is $125$, and crawls along the surface of the cone to a point on the exact opposite side of the cone whose distance from the vertex is $375\sqrt{2}.$ Find the least distance that the fly could have crawled.