Bridge-Passenger Deck
	Move the bridge-cargo bay iris valve to the forward and centerline allowing access directly to the main cargo area, allowing free access to the cargo deck and expanding the fuel hold area that will usually be used as fuel for economic reasons.
	Add a turret just aft of the bridge view port, for the extra firepower or extra cargo space (usually uninspected).
	Add an airtight partition to isolate the aft two crew cabins, allowing them to be used as passenger cabins.
	Move the crew-engineering iris valve forward of the partition, allowing crew only access to engineering.
	Convert one of the air raft bays to secured cargo hold, allowing it's use for conveying Imperial mail.  The most profitable cargo per ton.
	Extrude the nearby storage area iris valve to add two squares to it's volume.
	Convert the airlock space between the ship's locker and the Captain's cabin to an arms locker by eliminating the exterior iris valve and reinforcing the hull.
	Add an exterior iris valve into the crew lounge from above.
	Reposition the passenger area access to the air raft airlock to port, perhaps into the corridor to the extra passenger cabins.
	Slide the galley forward covering the crew lounge access, for that discrete restock or allowing the crew the chance to raid the passenger galley.
	Perhaps adding an exterior airlock to the passenger area to facilitate space side boarding.

Engineering Deck
	Eliminate the halls and iris valves in the fuel/ cargo hold areas.
	Add a floor iris valves near the forward landing gears and ladders on them for crew access to the ground.
	Remove the low berth area and create a cargo hallway between the ramp and engineering terminated in a cargo door into engineering.
	Reducing the maneuver size allows space for a workshop, the low berths, an extra passenger cabin (with lots of noise padding), and an little cargo space.  The cabin and low berths are connected to the passenger vertical tube, with a secured iris access to engineering area for emergency crew access.  The cargo area is directly accessible through the new cargo door and from engineering, perhaps for special cargo.
	The iris valve to the turret area is also slid forward even with the passenger tube, probably beside the crew-engineering valve.

Lower Cargo Deck
	Move the turrets forward to a port/starboard location, allowing better field of fire shrink the port/starboard airlocks but retain the side facing exterior iris valves.
	Convert the passenger vertical tube to a round passenger elevator, allowing access for weighty items and the physically challenged.
	Remove the vehicles to provide max hold space.

Total Picture
	While dirt side the exterior hatches above the lowest deck have limited usefulness (where external ladders would be required) in a primitive star port, so I limited access to the sides.  However for EVAs, some hatches above would shorten the safety line.