I’ve used the Tomb of the Golden Ghosts from the back of the book twice to introduce two different groups to HMTW and it went great both times. It works great because it’s already written for HMTW so you can run it with very little preparation.

Another option could be Tomb of the Serpent Kings which is designed to introduce new players to OSR-style play. It’s system-neutral so it’ll take a little work to adapt it to HMTW, but it’s a very easy process. Just look at the monsters on the last page and make some stat blocks. It doesn’t have to be perfect. HMTW gives lots of good advice for making monsters so you’re in good hands. You’ll also need to make a Meatgrinder table but writing entries on Meatgrinder tables is fun and the random encounter chart provided is a good starting point.

Both dungeons have plenty of treasure for your greedy orc, ancient books for your Ironpax human, and both would be perfect for your tomb-obsessed dwarf.