Sample Dungeon, Room N: "Ten stone sarcophagi are scattered about, four empty with the tops off. Six, however, are closed. If the adventurers open one, roll a die to see which they have chosen." Illustration by David C. Sutherland III
Zach Howard provided an in-depth analysis of the sample dungeon as part of his blog series of posts on the Holmes manuscript, starting with Part 46: "Zenopus Built a Tower", essential reading for anyone thinking of running the adventure.
Zach also published The Ruined Tower of Zenopus on DMs Guild, a 5E conversion with multiple appendices, including Further Reading, Dungeon Factions, Portown Rumors, Use with Ghosts of Saltmarsh, and Pre-generated 1st level characters.
An interesting bit of trivia is that The Official D&D Coloring Album (1979) written by Gary Gygax (with Lawrence Schick) and illustrated by Greg Irons, used the sample dungeon as the basis for its own map, as discussed, here.
One of my favorite experiences at Gary Con X in 2018 was a late-night pick-up game run by Andy Campbell, in which he ran a group of us through his version of the sample dungeon. Andy let me play a Cynidicean PC, and was a memorable DM.
A year later, at Gary Con XI in 2019, I had the pleasure of playing in Zach Howard's sequel to the sample dungeon, In Search of the Brazen Head of Zenopus. I played Zereth, while my son got a chance to play Maximillian the Centaur!