If you are building your own one way to make things easier (andi've done this for a shuttle myself) is to draw the outer then save that, then save the same model and the interior name, then reverse all the face normals and shrink the whole model a bit. This will give you an inner shell to work on.

Then it's just a question of moving vertices about and adding more internal detail.

The other option is to use something like Dedit (I think that is the name) to build the interior first, then put the shell around it.

The other option is to design some prefabricated parts from which to build all the station interiors from, then it's would jsut be a question of putting the prefabs together in a what that matches the shell....

Dean