My party has a long journey ahead of them and, instead of just jumping ahead or popping in random encounters from a generator, I was thinking of running a few specific, planned encounters/mini dungeons to spice things up a bit. One of these encounter ideas came to me last night, I love the general idea, but am a bit lost in how to implement. The encounter I was thinking is that a coven of hags are running a fake inn along the road the party is travelling, in the hopes of messing with some unwary travellers, as they so love suffering of others.  Hell, they might even be looking to grab a baby or two if a new mother or expecting mother happens to stop in. So, idea is that during the night at the inn, the hags plague their visitors with dreams, illusions, and other such things to reap the enjoyment they seek. I have a layout in mind and even a few specific ideas to haunt each of my PC's.

The problem I am having is how to bait this trap and how to populate the inn itself (small combat skirmishes with minions and familiars, other monsters, npc visitors, inticing red herrings causing things, etc.). Essentially, if it is just a creepy house in the woods run by 3 old women who seem a bit too interested in the PC's, this would be too obvious. So, I was hoping to see if you guys had any ideas.  Thanks in advance.

Maybe the inn is in town and the villagers know about the hags, but they are terrified of them and several important figures who have bargained with the hags have pulled a few strings. The pcs could try to talk to the townsfolk to receive answers, but it won't be easy.

If you think your players will be suspicious anyways, just own it.

After a day of travel, just when they are looking for the next good place to take a rest, there happens to be a inn at the side of the road. Three jolly old women welcome them into their home and tell them to rest up, relax, grannies will now take care of you.

Later in the night, have a group of loggers come by for a meal and a drink, a hunter pop in, a minstrel from the other direction of the road with a few songs and tales to spin.

By now, they will be paranoid and ready to fight everyone. They can be werewolves, fey, doppelgangers, or just plain commoners. And if the paranoia is entertaining enough, have the crones actually be: jolly old women, who like to take care of weary travelers.

I agree. A fake Inn is much harder to do that a real Inn, which has been subverted.

This gives the Characters more chances to notice that something is off. The townspeople are acting weird.

You know what the motives are for the Hags ( lunch ), but you'd need to decide what it is that is compelling the townspeople to cooperate. Are they being threatened or blackmailed? Are members of their families being held hostage? Are they willing accomplices who gain benefit from the arrangement?

Is the whole town in on it? Does everyone even know? Are there individuals who think something is awry and want to hire a plucky band of adventurers to find out what's going on?

Quick note, the idea would be this is just a random roadhouse stop on the way to where they are going not really in a town, or even near a town per se, more of a remote waypoint. So, I was thinking any "visitors" at or to the inn would be other evil fey or other similarly aligned creatures working with the hags to make sure the "lunch," as you put it, is well marinated in the fear and suffering before partaking.

Mind flayers and Intellect Devourers. They've got their tentacles in everything. Maybe they take the brains in exchange for helping the hags? That would make some sense...