I agree with Evilmikes idea. If you force yourself to build the level, you'll create a dozen of layouts, of which one eventually will lead to the needed layout for the level.
If you're building space bases you should ask yourself simple questions. Like "what does this space station need?", or "how should every part be connected?" and "Is this place meant for the masses or just technicians etc.?" and so on.
It leads to a global idea of what you want to create in JCS, AKA a layout...