This venerable Gygax adventure comes from his famous Greyhawk setting. It is meant to introduce new players to the setting. It is a short book (16 pages of meat, followed by many maps) and features but one dungeon with two levels. Pretty thin gruel.
Or is it?
Most of this module is devoted to details about the village and its inhabitants. So much so, that I cannot find an explicit mandate from an NPC for the party to explore the moathouse at all!
Instead, Gygax presents a module thick with role playing. The players, it seems, are expected to interact with a good deal of the locals, getting hints of their intrigues and, if there's time, go have a Scooby-Doo adventure in the creepy old moathouse.
In the hands of a DM that enjoys community theatre roleplaying, the village is the adventure. With wonderfully evocative place names like the Church of St. "Square corners can be pounded smooth" Cuthbert and Inn of the Welcome Wench (good luck publishing an adventure with that kind of name now), it is hard not to want to explore this town.
But again, my complaint is that as a combat-oriented adventure, it is a bit lacking. The moathouse is far from a megadungeon. I would guess that a party would clear it out in 2-3 sessions. Some of the encounters seem a little overmatched for a first level group. It needs to noted that Gygax suggests mixing in a few second and third level PCs into the group. You may need to tweak the encounters in the moathouse for absolute beginners.
Of course, there is a 6th level fighter named Rufus and an 8th level magic-user named Burne that will adventure with your party for a crazy cut of the treasure. That seems nuts to me.
T1 was meant to be the first act of two act drama concluding in the The Temple of Elemental Evil, which promised to be mind blowing in its unfettered awesomeness. However, as a standalone adventure for those without inclinations toward acting, T1 has perhaps too much detail on the town and too little in the way of monster bashing.
One of the great things about OSR today is crowdsourced enhancements. Just look at this color rendered map of Hommlet or this 3D version of the moathouse. Great visual aids and you get it for free.
I know this module is much beloved, but frankly, it doesn't fit my temperament at all. I am old enough to drink real beer with real ladies. I don't need to pretend to that in a fantasy town to make imaginary friends.