So, it's been a good while that I've been compiling ideas for an adventure I'd like to fill out/flesh out for Dark Sun. Problem is, I have all these ideas, but am drawing blanks on good ways to connect them. And as a heads up, I envision this adventure perhaps lasting 2 levels, and probably starting at 6th. I guess first off, here's a list of ideas I want to incorporate:
1. Gronk Spliteye is the main villian. He statisictally, is a bugbear, and has the whole bugbear look about him. Though he is not one (as they are not present in Athas), but was once a man like any other before some curse befell him, warping him into the monstrosity he is known as. The main idea driving this, and starting the whole idea of this adventure is a Reaper Miniature I picked up of a bugbear mini of the same name weilding a scimitar and mace, and I imaged him painted with a sandy base, and rough dusty metal armor. Then it struck me he could make an excellant villian for a Dark Sun adventure. The insipration behind his backstory I imagine, and plays a role similiar, to that of Calibos from Clash of the Titans. A mere mortal man cursed and warped into a monster who intercepts the heroes multiple times.
2. The finale of the adventure brings the characters to ruins uncovered by a recent sandstorm, a temple beneath the sands housing an ancient evil. A 4th ed remake of a "Crawling Apocalypse", or a "mummified tentacular beast". Or, see my profile pic.

3. The characters enter a region of Athas they've never visited, a region where this "Gronk Spliteye" (not sure about name) is known in infamy.
4. A plot device is stolen from the Dungeon Adventure "The Tyrant's Oath", where the nearby towns are opressed, but looked after by a bandit army. The leader of which will be confronted by the PCs in help of finding out Gronk's true intentions (whatever they end up being).
So yeah, that's what I've got so far. A twisted monster of a man wreaking havoc on a settlement filled barren expanse with some bad intentions for his actions, and the governing law of the area being that of a bandit force that simply wandered in and forcibly assumed control. All leading into a final confrontation with Gronk at the uncovered ruins before heading down and vanquishing an ancient guardian for some reason.
Any help at all from anyone on ways to tie this together? A few last comments would be that I would enjoy having a large battle scene portrayed as a skill challenge, also reminiscant of "The Tyrant's Oath" in the dunes near the uncovered ruins before the PCs chase Gronk from the battle in an attempt to beat them into the ruins. And a few other skill challenges mixed in would be nice as well, as my group enjoys them.
Thanks beforehand for any ideas anyone can spare

. And I don't have very long to prepare this, so I was hoping for some relatively quick replies. I have just over a week to get enough prepared for the start, though I'd like to just get it all typed up and done so I dont' have to worry about it.