When I first got into all this awesome OSR stuff, I download a CRAP ton of all the basic fantasy modules. Okay, I lied. I downloaded them all. After reading thru all of them, I love bits of some things, thought other bits were cool but wasn't sure about them, etc. I ended up drawing out a pretty interesting sandbox. Here is the idea.
I took the main map from the chaotic caves as the focus of the campaign although I planned to covert the whole thing to a hexmap. Rather than use the provided village, I used the fort from Morgansfort as it was just more my speed and I had waves of "god damn it I like the kotb, this will work facking awesome". The actual chaotic caves I left out, but I used all the rest of the triggers from the map provided.
I took the few dungeon encounters from morgansfort and popped them in there as well.
Then I took the premise from the adventure with Fonkin - DC1 Tales from the laughing dragon as the starting point for the whole thing!
Viola, campaign. just fill in the details.
And now my brain is really working! What might be cool is to somehow implement Allansia & Blacksand in there. Huh......