If X1 The Isle of Dread by David Cook, & Tom Moldvay is one of the greatest prehistoric wilderness & exploratory modules then when it comes to my Cha'alt/Godbound campaign where does it fall in my versions of California,Nevada,& Arizonia. There are a couple of resources that I began to turn up in my research. One is 'The Dinosaurs of California's Lost World' article by Brian Switek which is an excellent source of ideas for the preshistoric monsters on the island. The second article that I started looking into is the California current wiki article. The current view on the isle of dread is that its strongly connected with the Elmental Plane of Water via the endless seas. This being the case the elemental plane of water connecting up with California's seas is gonna be disasterous!
The lack of clouds along the coast (and also along the Central Valley of California)
is due to an offshore wind blowing drier air from the land offshore.
Not only are there going to be hundreds of alien species introduced but the disruption of Earth's seas allows foreign vistors to enter Earth's planar boundaries. This is because of the placement of the Endless Sea.
artwork copyright & trade mark wizards of the coast.
See the free OSR Mystara resource the Seas of Dread for even more prehistoric action!
Mystara & its various environs could merge & then vanish with no one being the wiser.
But somehow I doubt it given the nature of the isle of dread itself.
I've said it before that the isle of dread would be playing a major part within my campaign & given the fact that the slavers are operating with it. There's dinosaur & giant fish meat showing up within the fish markets of California & on many a dinner plate. But there's also far stranger cults showing up deeper in land. This is because of my scaling the encounters to deal with the player's expectations. And that's where the unholy trinity of Venger Satanis comes into play. The sea of worlds allows the "The Islands of Purple-Haunted Putrescence" to sneak in.
Because "The Islands of Purple-Haunted Putrescence" is outside of known time & space the perfect excuse is available to encounter a plethora of horrors. So I can sneak in a wide variety of lower tier encounters without having to skimp on quality. What we're looking at is a cross selection of undead, skeletons, humans, berserk warriors, slimes, goblins, and many of the weirder monsters of OD&D. This would also include lizardmen and more dangerous horrors as middle men & finally minotaurs and some giants as boss creatures. The Pulp aspect might be in the dungeon locations as the wreckage of flying saucers & space craft becomes the temples, stock dungeons, & ruin locations on the Islands now the home of some perhaps weird or mutated D&D monsters.
Both the island of dread & "The Islands of Purple-Haunted Putrescence" allow the players the perfect excuse to use a wide variety of OSR PC options & combined them into a party of adventurers without the need for complicated backstories.
The player's could use Barbarian Conquerors of Kanahu & Astonishing Swordmen & Sorcerers of Hyperborea adventurers together trying to survive against the alien horrors of the islands.
The Cha'alt wave has dragged in many additional planar elements into the mix of my campaign this includes "The Islands of Purple-Haunted Putrescence" & X1 The Isle of Dread. Everything here is keyed so that Astonishing Swordsmen & Sorcerers of Hyperborea will provide all of the necessary stats and monster profiles to set up & spawn any of the horrors for this campaign to succeed. The balance here is in the gonzo, weirdness, and otherworldly adventure that the The Islands of Purple-Haunted Putrescence thrives on along with X1 The isle of Dread.
This also means that many of the domains that are featured in these modules are gonna be up for grabs!