Hiya.
Since it seems we have wandered a bit off into "what I think makes a good D&D adventure module", here's one that I find
almost as perfect as
Keep on the Borderlands:
https://rpgcharacters.wordpress.com/maps/dysons-delve/
It's 11 (kinda/sorta 12, actually) dungeon levels. Each is on a map roughly 150' x 150' in dimension. Each level fits one
ONE PAGE...that's the map of the level, a list of entrances & exits, a wandering monster list, and the description/contents of each numbered location (about 12 per level). I used the compiled PDF of the above (available free DL on that link; just scroll down a smidge) for a 1e campaign that lasted about 8 months. In that time, they had just gotten to the 8th level. The story I had was that a young (9'ish) farm boy from a nearby village finely made good on his threats to his parents about "running away forever". His parents were a bit strict, and he a bit headstrong. Anyway, Billum was his name, ended up deciding to hide in the nearby caves his parents warned him to stay away from. He didn't come back. PC's enter and go on the hunt for young Billum. (there was/is a LOT more going on in the background that the PC's haven't quite discovered yet!).
The beauty of the above structure (lots of small maps, each level fitting on one page) is what I call the "ease of imaginative play". Basically, as a DM, you can take 5 minutes to skim over the dozen or so pages. In doing so, your imagination will automatically start to picture things and give you ideas; ideas you can use instantly to get the ball rolling. You can easily "wing" putting in specific info, NPC encounters, items, etc. so as to fit the story background you came up with in those 5 minutes of perusing. In my Dyson's Delve, I got the feeling of, for some reason, "water"; so I had the first few levels be an ancient "Old Faith" (druidic) focusing on waterways and fishermen. My descriptions of walls, floors, doors, knick-nacks, etc were all oriented towards that overall "vibe".
Long story short'ish...it was a helluva lot of fun for all of us! Alas, some nasty critters down on level 8 killed almost all the group (only the archer survived...and a newly rescued wizard). That said, everyone talks about it and is eager to start it up again and see if they can best the lower levels!
^_^
Paul L. Ming