Back to the Wilderlands of High Fantasy - Hacking the Wilderlands With Castles & Crusades - Mines of Custalcon By Bryan Hinnen

 "A booklet with full-color cover includes Mini-dungeon, Histories, Descriptions, NPCs, Maps, and Tables for two villages and 476 square miles of wilderness.  The first of a new "Wilderness Series" of playing aids that maps in great detail the Judges Guild's City State wilderness area, using the Campaign Hexagon System.  Twenty-two five-mile hexes, covering over 476 square miles of wilderness, are mapped out, as are the two villages in this area, Byrny and Trollslore. Keyed shops, inns and taverns, as well as histories and ways of life of these villages are provided.  Wilderness encounter tables and a three-level mini-dungeon in the ancient mines of a lost civilization beneath Trollslore are also included"

Mines of Custalcon is really dependant on two villages in this area, Byrny and Trollslore which are kinda almost but not quite blank canvases for the DM.  Byrny & Trollslore as well as the environs are really islands within the wilderness of the Wilderlands series by Judges Guild. 

 Mines of Custalcon By Bryan Hinnen is prime for a Neolithic group of peoples who established the villages of  Byrny and Trollslore. Trollslore itself is rife to become a base of lost peoples with deep connections to the Fae. And the whole area is perfectly suited to transition from Neolithic into Bronze  age civilizations echoing ancient  Great Britian according to Wiki; "Recent tooth enamel isotope research on bodies found in early Bronze Age graves around Stonehenge indicates that at least some of the migrants came from the area of modern Switzerland. Another example site is Must Farm, near Whittlesey, which has recently been host to the most complete Bronze Age wheel ever to be found. The Beaker culture displayed different behaviors from the earlier Neolithic people, and cultural change was significant. Integration is thought to have been peaceful, as many of the early henge sites were seemingly adopted by the newcomers. The rich Wessex culture developed in southern Britain at this time. Additionally, the climate was deteriorating; where once the weather was warm and dry it became much wetter as the Bronze Age continued, forcing the population away from easily defended sites in the hills and into the fertile valleys. Large livestock farms developed in the lowlands and appear to have contributed to economic growth and inspired increasing forest clearances. "
This gradual transition takes the wilderness from cleared land back into the deep wilderness of the Wilderland. This could help to explain the reestablishment of the monsters back into the 476 square miles of wilderness & the reason for the mini dungeon of the Mines of Custalcon.
The Roman style technology within the area is the exception & not the rule around the Mines of Custalcon. The City State of The Invincible Overlord's military forces have a vested interest within the Trollslore region. The real power of the area is the Fae & the close ties with the  two villages in this area, Byrny &  Trollslore. 
These powers concentrate some of thier power within the witches of the regions including the hags who are a part of the backbone of 'Witches of Court Marshes'. This plugs directly into the themes & wants of the Castles & Crusades Codex Celtarum 2nd Edition By Brian Young.

So we have Neolithic, Bronze, & Iron age style cultures interacting through the lens of the Wilderlands around Byrny and Trollslore. Castles & Crusades DM's would have to put in a lot of work with Mines of Custalcon By Bryan Hinnen. But this module's adventure  could easily become a part of a Wilderlands C&C campaign. We'll expand upon this coming!