Ok, it's kinda neat that in Burnt Offerings, Old Light is revealed to be some kind of ancient arcane artillery piece. I like that, it's cool.
But you can't very well plop down an old mysterious ruin in the middle of a town and not detail it at all in the first adventure! Players will immediately gravitate toward it when you give them the Player's Guide map to look at. They'll want to check it out right away.
I rather expected Burnt Offerings to feature a dungeon under Old Light. Putting the dungeon under the Glassworks instead was a surprise that left me wondering how the heck to handle the inevitable "My character wants to go explore the Old Light!" requests.
Sure, I can say some variation of "there's no way in" but that's kind of boring. I'd want to at least stick a couple dire rats or whatever into a ruined room accessible through a narrow crack, or something.
Is doing this going to screw up a future adventure in the RotRL path? If yes, then what's a good alternative? Is there anything under Old Light that we'll learn about later?