Once again "the Dark Company" (1992, included with "Advanced Quest/Master Edition") is widely misunderstood.The original quest (which was intended as an EU exclusive) was only ever meant to be played with the core game system plus the 12 red Mercenary figures (with 3 of each type of weapon available) to be used as "dark warrior" monsters.You don't really even need that many of these as you never face more than 5 of them at a time. The entire board doesn't need to be setup all at once to play these... the heroes are traveling through a small "slice" if you will of each board before they cross over and "reset."
The whole idea of playing a board game and NEVER re-using assets is pretty silly. It's an exercise in sheer ostentatious wealth, similar to throwing away your dice and unwrapping a new package every time you roll (maybe if you are running a busy casino and worried about fraud, you'd swap them out every hour?).
It's like the people who say they want to play Monopoly with REAL CASH. Okay, that's kind of an awesome one-off idea, but is it really worth the trouble for most people?
Yes, there are a few errors, like a repeated Fireplace or Weapons rack, but the quest kind of fixes itself. Those pieces of furniture don't do anything, they're just taking up space in mostly empty rooms.
Even if you are playing this with Phoenix's "NA conversion" (which frankly is probably a bigger source of confusion since it's rather hard to read without the color coding found in the original "poster") with a group of overladen heroes who have played the other North American expansions, there should be no need except for the small number of collectors/hoarders who happen to have multiple opened copies of the game who just want some excuse to create a spectacle on the floor (who has a table big enough for four simultaneous boards, never mind reaching across or running around the table to set everything) that was not actually intended by the designers of the adventure in the first place...
Don't get me wrong, it would be a "sight to behold" but the cheapest and easiest way would simply be to either print a bunch of stuff for a $100+ (more likely) to find three friends who have HeroQuest so you can put your sets together for this "once in a lifetime" event, which again, was not intended by the designers of the quest.
You don't ACTUALLY need any extra pieces or boards to run the quest as intended. Does it suck? Some say it does, but then you can mod it to your liking, including doing away with "duplicate" furniture.