Any Suggestions for Reskinning Adventures?

In my current campaign, there are two adventures that the party is likely to want to tackle in the near future. I'm hoping that I can reskin some pre-written adventures to fit what I'm looking for. Basically, I want to save some time and effort in terms of cartography, monster stats, some unique magical effects, etc. while changing and adding a bunch of other stuff to match my particular campaign. Here's what I have in mind:

First, the party wants to use time-travel magic to alter a key event in history. Instead of literally going back in time, I figure the party could use a mystical artifact to travel to a surreal dungeon which serves as an abstract representation of time/history/fate/destiny. By interacting with various features of the metaphysical dungeon (like convincing the Moirai to cut or not cut certain threads, or hacking the Matrix, or whatever), the party could alter the past in precise, almost surgical ways...albeit limited ways, and probably at some hideous cost, of course.

Second, the party will probably want to enter the Sealed City of Duvan'Ku, deep in the Untamed Lands, and try to undo the evil curses placed on the world by that empire of cruelty. This may very well serve as the climax of the whole campaign, so I was thinking about making the city (or some structure within it) a megadungeon chalk full of the kind of hideous magic found in adventures like Death Frost Doom, Death Love Doom, and Fuck for Satan. If they can get to the heart of this labyrinth, the party may be able to find a way to stop a dreaming god from awakening and ending reality as they know it...again, at a hideous cost, because this is the cult of Duvan'Ku we're talking about here. Nothing is painless with them.

Here's a list of pre-written adventures/modules I've already used in the campaign in some capacity, to the extent that I consider them disqualified for use in this reskinning project.

• A Stranger Storm (LotFP Referee Book)
• Tales of the Scarecrow
• Tower of the Stargazer
• The Pale Lady
• The Flayed King
• Oil and Water
• Fuck for Satan
• No Salvation for Witches
• The Tower (Green Devil Face)
• The House of Snails (Green Devil Face)
• Fantasy Fucking Vietnam (Green Devil Face)
• The Monolith from Beyond Space and Time
• A Single, Small Cut
• Death Love Doom
• The Stygian Garden of Abelia Prem
• Lamentations of the Gingerbread Princess
• Forgive Us
• Hammers of the God
• The Bloodsoaked Boudoir of Velkis the Vile
• Thulian Echoes
• The Idea from Space
• Beyond Mere Lotophagi (Green Devil Face)
• People of Pembrooktonshire
• The Seclusium of Orphone of the Three Visions
•  Death Frost Doom
• Scenic Dunnsmouth
• The Gem Prison of Zardax
• Towers Two

There are some other books/products I've used which I don't consider disqualified, so they are not listed here.

So, any advice? If anyone has any ideas to share, I would greatly appreciate it.

UPDATE - OCTOBER 1, 2016

I received a lot of great suggestions, so thanks everybody! Here's what I've got so far.

Time Dungeon Ideas

1. Hero Quests (from RuneQuest)
2. Old Planescape adventures
3. World of the Lost

Duvan'Ku Dungeon Ideas

1. The Forgotten Temple of Tharizdun
2. I1 Dwellers of the Forbidden City
3. Deep Temple (from Snake Pipe Hollow, RuneQuest)
4. Maze of the Blue Medusa

Ideas for Either Dungeon

1. Deep Carbon Observatory
2. Monster Island (RuneQuest)
3. Book of Quests (RuneQuest)
4. Bad Myrmidon
5. Vortex (Numenera)
6. The Devil's Spine (Numenera)
7. A Red & Pleasant Land
8. Misty Isles of the Eld

UPDATE - DECEMBER 6, 2016

For the "Time Dungeon" adventure, I ended up using a combination of Deep Carbon Observatory, the underground "wilderness crawl" from Thulian Echoes, and the dungeon from World of the Lost. I think it worked out really well, so thank you again for the suggestions, folks. Now I just have to decide what to do about the "Duvan'Ku Dungeon."