Small update to this idea.
I have done a lot of writing to the super module since coming up with the idea.
Some background I converted, with original module stuff in quotes:
Khalitharius is now a powerful ice demon prince, imprisoned by an Elder Magi (Martek) several hundred years ago. Knowing his trap wouldn't keep the demon confined forever, this Magi sought a way to destroy the creature. In his search, he discovered an area of great mystical and dimensional power (call it a ley line nexus or some other magic babble), but it was depleted and was going to take time to recharge. Once it was however, the Magi knew he could build a weapon to force open a Shadow Gate (in Magnamund, interdimensional portals are called Shadow Gates and are rare and unstable) and banish the ice demon for good. The Magi contructed a citadel and made it the weapon (Sphere of Power) that would open the gate as well as being a magnet that would attract the ice demon to it once activated. The Beacon and the Citadel both need to be activated to make the plan work.
Activation requires five Crystal Prisms (Star Gems) that the Magi spread amongst the people of this frigid wasteland. One of the Prisms will actually release the weakened ice demon...this needs to happen for the Beacon to be able to attract the creature to the Citadel.
The Raurindi become the Ice Barbarians of Kalte, a brutish wandering clan type folk whose numbers are greater in the east end of Kalte than the west (where the quest will begin). The Durpari become renegade Drakkarim, an ethnic group of humans driven from their homes in the south seeking a better life than making war and toiling under a dictatorial regime. They have settled in this harsh cold wilderness and have begun to make a life. They are militaristic, rugged, and survivalist.
My plan is that the Drakkarim will be concentrated heavily in the western portion of Kalte where the quest starts and thin out as the PCs travel east. The population of Ice Barbarians become more signifigant as they travel east.
The last civilized bastion of Drakkarim will be a small outpost on the edge of a frozen lake (Oasis of the White Palm).
I've got more and will type more later.