Hi, I would like first to share my thoughts about this topic...
The videogame has different mechanics than the boardagame but I would like to see a conversion to the board game as much close as posible to the original rules of the board game. I think the success for this fanmade questpack depends so much in trying to use as much as posible all the official available material, trying to avoid creating a new board game, except those especific key topics of the videogame which should be introduced with new mechanics.
I like the idea to simulate the same number of monsters encounters from the videogame to the board, not the same for the traps since they are so many and I think it has not too much sense including all of them, just the feeling is important. Moreover there is no enough space in the board for such quantity of traps and it would create non-playable quest maps. However, I understand that including all the monsters from the video game in the quest maps will make difficult quests, of course, but I think Legacy of Sorasil is a good opportunity to allow the players playing from the beginning with overpowered heroes, even with the new heroes from the videogame if they want, so defining new stats for the four classical heroes and the new four ones should be done for this questpack, but I would not allow playing with more than four heroes at the same time since the videogame, like the boardgame, does not allow it.
As first ideas for the characters, I would called the classic characters as "Expert Barbarian", "Expert Dwarf", "Expert Wizard" and "Expert Elf", and the new ones the same as mentioned in the videogame manual. For Expert Wizard I would allow him for example casting an extended catalogue of spells from the already elements decks, inspired in the ones shown in the videogame manual (but not only those ones). For the Expert Elf I would allow him casting spells from three of the elements decks like the Wizard in the basic game, an so on. For fighteing characters, I would gave them higher basis BP and MP than usual and an starting ammount of money (quantity TBD) to buy equipment to allow them starting well equiped. They are only raw ideas by now but that's what I have in mind by simplicity. Anyway, characters redesign will have so much freedom so I don't care too much at this design stage, they would be adapted later according to the maps we already had designed.
I have read some posts (I don't remember where) telling the desire to have one quest map per videogame level... In my opinion it is so ambitious, I think splitting some of the levels in two quest maps (or more) is better to cover all what this questpack can provide instead of compressing it too much from the beginning, probably losing too much original information. The only stuff I would reduce a bit are the outdoor areas, since HeroQuest rules work well inside dungeons but outside them I think it has not been tested enough so their weight in the overall playthrough should be reduced but we will see...
About monsters stats... of course they should be fully defined. The videogame could give some inspiration but videogame's combat mechanics are different than the board game so I prefer defining them just by comparison with other official monsters of HeroQuest.... One final note: I don't have problemas with any monster from the videogame... expect the Beholder, it is a clear D&D monster, so if possible I would like replace it for another one. Nevertheless, are we sure such monster is called "Beholder" in the videogame or does it has another name? If it has another name, modifying it would be much easier I think

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And finally, how I think is the better way to make this questpack... I have in mind this steps:
1.- Extract from the videogame's levels as much info as posible. Fortunately there is much info available, but it should be checked. For example, the fanmade info I had from Level #1 was incomplete, I checked there were a Potion of Healing and some monsters missing that they exist in the videogame.
2.- Make a first version of quest map/s for each level, i will call the "master" version of the map, as much accurate as possible to the videogame but following these criteria:
- Respect as much as posible the same possible paths the heroes can chose during the videogame. For that can be used several tricks, like using more rooms, tunnel traps, etc. if they could be well implemented.
- Respect the same number of monsters.
- Respect where are the traps... but not necessarily exactly the same number of traps.
- Respect all the rewards provided to the heroes in the videogame and where they are found. The rules for the artifacts found are not important at this designing stage.
- Try to respect if there is enough space the furniture shown in the videogame but only if does not reduce the gamming experience.
- Try to re-use as much as possible all the official game components from basic Game System and the expansions, not only their type, also their quantity (I assume everybody who will play this questpack has all the expansions as good HeroQuester

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- Double doors... They do not provide to much to the board game, so I think they may be replaced by single doors as possible.
- Check if the videogame allows the player vising the Armoury after completing the quest or not since such information would be included in the quest notes (as example, like Stephen Baker did in Profecy of Telor questpack)
3.- Identify and list all those things from the already designed master quest packs which may need custom components, like new monsters, new cardboard rooms, etc... If step 2 was well done, they would not be too many.
4.- Think about alternatives to be introduced in the master quest map which could improve the board gamming experience without changing to much the original feeling of the videogame level, some usual examples, but not the only ones are:
- Eliminate most of all those minor rewards that may be obtained by dawing cards from the Treasure deck. For example all those rewards below 100 gold coins which are not inside any chest, even some Potions of Healing. If the videogame includes any new frequent minor reward, I think it would be a cool idea to create a Treasure card for it like other official expansions do.
- Decide which Wandering Monster should have the quest. I suggest selecting the most common one in the quest and reduce their number in the map according to how many wandering monsters could appear in the quest (estimation).
- Relocate rewards if they could provide more interest in other areas of the map, or even recolocate them in other quest if there are reasons for it.
- If quest difficult seems to be extremely high, try to reduce it but of course this will probably change a lot the original charm of the videogame level so it should be avoided.
- Think about stats about new monsters, characters, special gamming mechanics, etc.
- Introduce minor changes which could simplify the required game components, for example replacing secret doors by regular door if it does not change too much the original charm.
- Reduce number of quest notes, eliminating the non used ones or grouping the similar ones.
5.- Create a "fanmade" version of the "master" quest maps attending to the alternatives thought in step 4 but always preserving the original master quest map in order to allow tracing which of those changes are invented by fans and which of them can be found in the videogame.
6.- Define the stats of the new monsters, monsters characters, new mechanics.... and also the artifacts.7.- Create the final playing version of the quest, writting all the intro, all the notes, etc. for printing.