Well, that is what I mean. The build the level thing.... ah, damn it. I am doing a poor job of explaining this. When I say "build the level", the thing you see is part of the pathway. What I mean is that I won't build the hull first... I will build the detail brushes first, and the hull afterward! This way, I don't feel constrained by the arbitrary limits of my own structural hull.
If this still seems like a bad idea, I'll show you in Radiant, after I get a bit done. In the meantime, I've sketched out part of what I want in Paint. I'll use that as an extremely general template for Part II. Part II is one long level, like t3_rift. Part III, The Valley Catacombs, will be rooms, enclosed by ceilings, walls, etc. But for now... *opens Radiant*