I'm one of the players in Koramado's campaign - and occasional sidetrek DM.
Our group, too, wanted to go after Gottrod's lair, so I thumbed through my Dungeons for something to use. Then I stumbled across "Old Embers Never Die" from issue 100.
Since its a sidetrek and our party as 8th level at the time, I toned it down. I took the kobolds from the first part and made them the guardians of the lair in the second part. I toned them down as follows: 2 4th fighters, 2 5th rogues, 1 9th druid, 1 8th fighter, 1 8th sorcerer, and 1 7th/2nd cleric/dragon adept. I made all the dire rats standard dire rats, the elemental huge, and got rid of all the lake denizens save the druid.
The setup was the the druid was in monitor lizard form swimming in the lake and the fighters and rogues were armed with bows and stationed up on the crater rim (where they couldn't easily be seen). As the party followed the trail along the edge of the lake, at a given point the druid (using Natural Spell) started hitting random party members with Call Lightning. This was the signal for the fighters and rogues to open up with arrow fire. I assumed the first arrow each scored a hit with was poisoned, just to make things interesting! When the party damaged one of the archers for more than half their hit points, the injured kobold ducked down into some kobold-sized tunnels, to reappear later and fully healed. The party never did figure out about the lizard.
The next section was the tar pit room, where the soecerer used his familiar to drop the portcullis and separate the party. The sorc hit the party with spells until he too was damaged, at which time he ducked into another one of those tunnels. He was guarded by a dire rat on either side so that he'd have a chance to escape. At the same time the druid and her familiar hit the party members on the other side of the portcullis.
Finally, the treasure room. The obvious denizen walking in was the kobold champion fighter and two dire rats. When the party moved in to attack them they were hit from both sides by missile fire from the reappearing rogues and fighters. The round after fighting started, the sorc and cleric made their appearances (in my action the druid was killed while the pary was split). The sorc resumed attacking and the cleric summoned the elemental, and a final combat to the death ensued.
At the time our party had four of its six members present. Mine was (conveniently) in jail for fighting with some half-orc mercs, and another was alte to the session. Although everyone in the party was 8th level, if I hadn't pulled some punches it would have been a TPK. As it was there was one death and one unconscious.
Note that the kobolds in the original adventure had equivalent appropriate to their (higher) levels, so you'll want to tone this down - especially not allowing them to have dragoncraft armor, which would really increase the loot value. For their misc treasure, I just used their list of loot from the adventure. For Gottrod's, I just used the list for a CR10 dragon (we ran Gottrod as a juvenile, though damaged) from the Draconomicon. Be especially careful about the kobold champion's AC: I made it 27 and he was almost unhittable.
Note: the crater map from the original Flame adventure in Dungeon #1 is full-page and on hex grid. Also the pictures make nice additions.
