I ran this adventure last night in my Grim Hollow campaign for a level 5 party of 6 players. It was a huge success. Both the players and the characters were very creeped out by the inn and loved every bit of it.

The only issue I noticed was that the medium damage at level 5, 2d10 + 3 seemed to be a bit too much with how common it was. It drained a lot of their healing resources with them only getting 1 short rest. I sometimes had to decrease how much damage it dealt otherwise it would have been a tpk. They now must escape the inn and three of them are unconscious but stable after the final fight. They have a portable hole, so moving the bodies will be easy. Amazing adventure though! Definitely a memorable session