if you're creating this level in a modern engine, you're going to probably want to do it modularly or somewhat modularly. I generally design spaces using lego pieces (and i do the same with organic stuff) build out the tunnels as re-usable tunnel pieces... and change the props and lighting in the tunnel to make it look…
You could do the tunnels with splines, which you can extrude shapes onto or if you have max, make it a renderable spline with geo. The main pods can be started from a sphere or box or plane - whatever, really. Then you just stitch em together. If you want to do it modularly it's pretty much the same way, but you'll have to…