Holdings of the Zombie Queen

I would love to run a campaign of Encounter Critical!, for money though, and if I am going to charge I should have a decent idea of what the Mighty World of Vanth looks like where the game starts. I think I want to start PCs in the north east of the continent. From the Slaver Kingdoms in the north all the way down to The Forbidden Waste and the Unknown Highway. The names for areas of western Vanth all have a fantasy taint to them. I want to stay more gonzo space fantasy. Steel Warlords, Ape Sultans, and Darth Viraxis feel more in line with Mad Max/Gamma World then does City of Blackhawk and the Silent Glade. Though the City of Bloodhaven may have promise and The Limb Traders is dope as hell.

But my eyes are irresistibly drawn to the Holdings of the Zombie Princess. I envision a cracked, dead land endlessly broken by narrow ravines, carved over millennia by acid-rain storms driven by violent, pale winds. The Princess's Keep, her Holdings themselves, are these same cataracts found everywhere else in the realm repurposed by the gods for who knows what purpose. The Zombie Princess uses them as a vast subterranean prison to cage the living and her hungry horde of Zombie Armies. 

It is very difficulty to travel the land without a knowledgeable guide, someone who knows how to navigate the twisted and blasted landscape without getting hopelessly lost. Unfortunately this leaves only the feral ghouls which haunt the black corners as such people, and they are more interested in eating you then being of service. The numerous cannibal tribes of dead flesh eaters nightly crave live sacrifice for their evil rites spoken in ghastly gibberish. These hungry hordes plague their nearby neighbors with continuous raids and infuriate the Slave Lords the most. Passing the Holdings along the Unknown Highway has become untenable, and the Klengons refuse any entry to their mountain colonies to the east. If the Slaver Kingdoms need to search westward for buyers, the people of the east become the supply of new slaves being sold in the other direction. Viraxis would not want to see their situation reversed, and has agreed to assist in a joint venture to gather intel on the Zombie Princess's power and strength. Enter the PCs who now must travel through the Holdings and seek court with the ruler of the dead. To find out what it will take to curtail ghouls raiding the Unknown Highway. 

I would crib T2-T4 The Temple of Elemental Evil for the underground city of the Zombie Princess. I'll read over the module itself and see if anything else is worth lifting, or just the maps.