A trick to make things match is to use a cube that contains all - as reference. If you use that in your scene and with all imported meshes it should be easy to position things and the scale should be ok already when you bring things in. The terrain size to me sounds like huge. But a case for a procedural terrain that Vue 5 offers. That you can go as close as you want and the resolution will be ok always. In Vue 5 we only still struggle with a memory issue that hopefully will be fixed soon but could make it difficult to deal with big scenes. Oh, not to forget that you maybe can switch off the automatic resize and reposition option in the preferences.

One day your ship comes in - but you're at the airport.