Eh, I have found that you can run AD&D modules on the fly in 5e. It's really not hard.
Yes, we've done the same. It's actually surprising how well AD&D module encounters create CR-appropriate challenges in 5e. Occasionally we've needed to change things like add or remove quantities, but it's nowhere near as complicated as having to do a 3e module on the fly.
But more importantly .... 60% empty corridors? What are you talking about? I can think of reasons not to play earlier adventurers, but ... that's not one of them.
They needed a lot of empty space to pad things out. Empty corridors and rooms were vital to how the game worked attrition.
Remember, you're supposed to roll for random encounters every hour (i.e., every 6 turns) in a dungeon, and there's a 10% chance for such an encounter. Further, moving in 1e was really slow while exploring and mapping indoors. 1" of movement is 10 feet traveled per turn, and the normal unencumbered movement rate was 12". So indoors or underground while exploring and mapping, you're only moving 120 feet every 10 minutes, and exploring rooms takes 1 turn per 10 foot by 10 foot section. That's 720 feet an hour, or somewhat over a mile for an 8 hour day of travel. If you're exploring and mapping more than 7 hours, you've got a greater than 50% chance of at least one random encounter each day. That's why nobody wanted to rest in dungeons: 8 hours of rest is a 57% chance of at least one encounter! Nevermind that you only got 1 hp back!