Just found this site. (I’ve been avoiding reddit lately.) Now I’ve got an incentive to make D&D memes again. Migrating my old stuff gradually while I come up with new ideas.
Megadungeons are a bit of a relic from previous editions, when mapping was a large part of the experience. If you're going to run one, I recommend using B/X or even OD&D and perhaps scaling down a bit - Old megadungeons were made when entire college dorms played in a single campaign, and were meant to grind down party resources.