Even in a dungeon crawl, you can improvise a lot. The contents of the rooms, spells and secrete doors, treasures. I don't know that specific dungeon, but I've never had a D&D game, including a dungeon crawl, where everything went as the module planned.
It's useful to read ahead if you can, the you can seed hints of things elsewhere in the dungeon.
A DM-only copy of the map is really useful, so you can make any notes you want on it. Paired with the list of rooms and what's in them - that's where I'd note down for myself what the players did in each room, if there was anything interesting not note down besides "cleared".
drailin