I'm running through some of them now. After using The Lost City, I'm expanding the "Zargon Plot" using some of the guideance in 3e's Elder Evils, which provides some seeds for a campaign that revolves around Zargon's rise. I'm using that as the framing device for the other adventures, rather than the Inifinite Staircase, which I found kind of....bland, in the end.
So, like, the party was hired by Vanessa Mackelroy (from Elder Evils) for the initial expedition and, having completed that, is now rescuing Dorn from gnolls. The weather will start to turn. Then, we'll have Vanessa send them on to the next adventure in the series. When they return from that, they'll find the Juiblex cult and Vanessa missing. And so on, until they return to the Lost City for the big confrontation at the end.
Using some of the material from 3e's Sandstorm and 4e's Dungeon Delves, too, to add a bit of texture to the adventures in between the main ones.