The Drowned Menagerie - Spoilers

[Exitilus]

I'm about ready for my players to come to the Drowned Menagerie in the 2nd Module.

I'm looking at the map and trying to figure out how they move from room to room, as well as how they get up to the Cat Walks above? It appears all the doors are closed. So they would have to climb up every chamber and then climb back down. Feels like a lot of work when they can just climb up once and then take the high bridge to the Tower, leaving everything else behind.

[Windspirit]

Spoiler:

As said on page 55:
The four containment chambers have ceilings 40 feet high; the iron catwalks originally hung 30 feet above the floors. All of the interior walls are slippery with moisture, and require a DC 25 Climb check to climb. Unless otherwise noted, all doors opening onto the containment rooms are bound in iron and barred from the outside (hardness 5, hp 20, Break DC 25).

For me that means, they need to open the door(s) from K3/K5 or K6/K7. As they are easy to be opened as they are locked from the K3-K6 side.
To move between K4/K5 and K7/K8 they would need to break down the doors or use a knock spell. (I guess Caromarc used a spell to close them in the first place, else...not sure how they both can be closed form the outside...)

Once the Monsters are defeated and the characters can:
a) fly up
b) climb up 30ft (one climbs up and uses a rope for the others)
c) use a rope with a hook and then climb up (reduced climb check)
d) Stack the Iron cages from K4 and some rest of the Cat walks that are in K4,K5 and k7 and build a make shift "constructions" to get up to the 2nd level.
e) stubborn characters my also come to the glorious solution of digging 20 food thought rumble and excavate the K2 connection to the upper level.

If the players end up on K9 (the parts that don’t connect to K11)...they might need to go down and UP again...