Usually I export whatever terrain/geo I have as FBX from terragen so I can have the geo in Maya, scale it by 0.001 to match Maya's scale and animate from there. Using a curve and animate the Camera with a motion path works great. FBX import works great with cameras and you can have a perfect match.
Also best practice would be to duplicate your camera, parent it to itself and bake all its keyframes before exporting an FBX for Terragen.
But I am not sure what you mean by "sequence those imports"?