For those who may be interested (vaderios, you've done some fantastic matte work. It would be interesting to see what you or a more professional artist could do):

Here is how I figure the carbonite sequence goes:

1. Han, Leia, Chewie and 3P0 come in through this gantry
2. Han is encased in carbonite
3. Luke enters through a lower gantry...
4. ...which then justifies him coming up through a vertical hatch from a lower level in the carbonite chamber.
5. Vader falls from Luke's attack, and Luke drops down to follow him.
6. Luke enters the tunnel toward the Vent Pod
7. Luke is force-thrown out the observation window
8. Luke (using force powers) grabs ahold of the walkway, and then procedes to the Vent Pod access door
9. Final confrontation with Vader.

The Vent Pods could be moved up closer to the carbonite chamber, but even so it would not be too far off that Vader had a back-up plan and led Luke to a secondary trap (Luke could use his force powers to track Vader, so having to go through a lot of stairways and hallways to go to the much lower Vent Pods wouldn't be too much of a stretch).

I don't know how this works, but here is an alternative blueprint:

I don't know how the entire carbonite platform would fit inside the very top without completely re-designing the Pod,