Heheh.. oh, this thing's only just begun, so it'll be all sorts of changed before it's done.  I see what you mean about the pylons, I might rework those, but the stretched connection ties into the nacelle design I have in mind, so I'll see how it looks with those before making any major changes.
Anyway, to continue... once you get the top view of a part kind of laid out the way you want it, you need to add depth, so I switch between the side and perspective views (sometimes front/back) and drag the points of the splines into their vertical position.  
The key is to make the splines line up with the ship's contours in two views (or more if you can do it).  Once you do that, you can get a rough outline of the ship's major contours.
Once you have the major lines traced, you basically have to connect the dots so that they're connected by enclosed triangles or rectangles (while you can draw 4+ sided polygons in max, surface modifiers need quads or triangles).  Once that's done, you can apply a surface modifier, and it'll convert the splines into a mesh.  Be careful here though, and make sure you use a very small weld radius, and set the "step" option to zero, unless you want all of your edges automatically divided, which will basically subdivide all the rectangles and triangles you've outlined.
That mesh I posted the pic of above was roughly built all in splines, and then I added the surface modifier to start adding detailed sections.  
As for the parts breakdown.. actually, aside from the nacelles and bridge, and other assorted tiny details, I have the entire saucer/hull/pylons of the Sovereign as a single mesh.  I'm really picky about smoothing and sharp edges, so often I'll go through the model and weld or break individual vertices to get the right look to the surface.  The Sov is one helluva complex shape, and has lots of relatively sharp edges that blend into curves, and I kept most of it one mesh so I could smooth the joints between parts better.