Thanks for all the kind words! I'm so pleased to know this thread is useful, and am very much indebted to Sagiro. We play next Thursday; we normally play every other week, but last weekend I ran a house-con for old friends (47 people, 26 games, in 14 different systems!) that sort of ate my life for the week.
I have something particularly fun planned for next week, assuming we get to it, but I don't want to give spoilers. Instead, I'll talk a little bit about what's happening in my other campaign, because it's going to be an example of how to re-use and re-purpose a dungeon.
My Merchant Prince game also takes place in Capria but largely on another continent, with 3rd lvl PCs who are scions of one of the most powerful merchant families in the empire (the Ridolfis, purveyors of spice to his most August Serene Emperor.) They're currently on a jungle continent tracking down a missing family servitor who reputedly discovered something incredibly important for the family before he disappeared.
In the last few games, they destroyed a young green dragon who considered himself a God. They tracked back to his lair, a ruined tiefling temple infested by devolved and wyrm-touched kobolds. As they explored the rubble and trap-filled shambles of a once-gorgeous temple, it became clear that it was exceptionally old, tiefling designed, and dedicated to Cenox, hellborn lord of pride, one of the fiends who granted power to Bael Turath so that they could conquer the dragonborn empire of Arkhosia. Yeah, yeah, whatever, nice flavor text. Until they killed the last kobold...
...on the altar...
And something walked out of the fiery pit. Something that looks an awful lot like those statues of Cenox himself. Who then clucked his tongue, raised his hands, and the entire temple changed back to what it was 900 years ago.
We haven't played all this out yet; all the PCs know is that their dragon treasure sitting on a basalt floor just disappeared when the floor turned into magma. Now (assuming they survive a conversation with the fiend) they'll eventually need to leave the temple, and while the physical layout is the same, every monster, trap and challenge has been shifted from something draconic to something fiendish. Ought to be an interesting challenge. And hey, I don't have to draw an entirely new map!