I ran this as a one shot for four experienced level 6 characters and we had a fantastic time! There was enough deadly adventure to keep them on their toes and nervous about entering each area after the first encounter with the shadows.

I tweaked the encounter option with the archfey to have him trail the party as an invisible pixie from a distance allowing him entry to the final chamber where he attempted to abscond with the goblet - a high action escape ensued and everyone was hyped afterwards. I am running my second group through this content and in my experience it takes a fair bit longer than the 4-6 hours noted. It was about 6-8 hours for our session pace in the first group