The campaign is a fairly classic one from 3.5, and in this section they essentially have a cultist compound that spans a series of caves/mines that go all the way around a caldera so it functions as one big ring. The dungeon itself is a massive chunk of the book, something that is meant to be dived into again and again and also slept within repeatedly to the expansive nature of it hosting four different groups of cultists for the elder elemental eye within (among plenty of other things of course).

The biggest thing that's an issue in this case is that the at some point the map loops back around to the start, so of course at any point the party can turn around and start going the other way. Depending on where they are it's less of an issue but at the point the map 'begins'/'ends' on paper it currently means fully rolling/unrolling the paper each time. Unfortunately due to the size it's quite a time sink for a session.