There are a number of techniques people have used with the Mythic GM Emulator with some success:

1. Use Mythic to rewrite the adventure.

If you want to play as a PC through the adventure but don't think you can separate player knowledge from character knowledge, try this option. Treat the module as rumors the characters may have heard, or dreams they may have had, about what's to come. They think that's what they'll be facing, but the truth could turn out quite differently. For every scene or encounter, roll on Mythic's Fate Chart to see if what's written in the module is true or not. If not, ask more questions to find out what the scene is replaced with. In effect, you're rewriting the module as you play through it.

2. Use the module as inspiration only.

Play as a player character and use Mythic as usual. The module may give you the opening scene, and you can interpret your Mythic rolls based on what inspired you from the module. The result will be a different adventure, but it will retain some of the elements that you liked about the original.

3. Separate player and character knowledge.

Play as both GM and player, switching between the two roles. You could even forget about Mythic if you wanted. When you step into the shoes of a player character, try to pretend you don't know what you read in the module and imagine what your character would do. You could even craft some interesting dramatic irony with this technique.

4. Play as the GM and emulate PCs the same way you would emulate NPCs with Mythic normally.

When you create the characters, if your game system doesn't already include this, determine each character's motivation and/or personality. You could use Complex Questions from Mythic Variations to generate this, or even to come up with the whole character. Knowing their motivations and personalities will help you interpret the answers Mythic gives you. If during the game you get an answer that doesn't seem to match up, try to delve deeper and figure out what's different about this situation that caused the character to act differently. People do change over time. Your emulated PCs will still surprise you like those played by real people. There is a good example of what this looks like in actual play here.

Don't forget that you can use Complex Questions if you aren't sure what direction the PCs might take the story in. These give more complex answers open to wider interpretations than merely yes or no.

In addition to the normal Mythic questions, for situations in which there are multiple actions the PCs could logically take, you could instead weight each one as this person did:

I used 50/50, 33/33/33 and 25/25/25/25 when there were multiple possibilities. Sometimes, I had 50/40/10 because some options seemed much more logical than others (adventurers explore the room they're in before running to the new doors, right?)

This fourth method could of course also be used to emulate players for campaigns of your own creation, without a published adventure module.

A couple things to note:

With some of these techniques you may not need to use Mythic's chaos factor because the module already presumably brings the action to a climax by the end.

Remember that you don't have to ask a Mythic question for every little thing; ask just enough to get a logical interpretation and go with that. Mythic itself suggests a two-question limit.

I have now DM'd the final boss fight myself. So, as no one with direct experience has thus far responded to the question (though many of their suggestions were good), I've written up my own experiences, detailing what went well and what went badly. Hopefully this will be useful to the people who have favorited this question, some of whom may be currently DM'ing LMOP themselves.

1. What approaches have you used successfully in your own game to make the final encounter with The Black Spider 'memorable and exciting'?

   • We'd played the entire campaign up to this point in the theatre of the mind. Suddenly revealing a full map and playing pieces for this fight definitely added excitement and grit, it also really helped to keep track of the AOE spells (faerie fire, web, darkness etc.) rather than me feeling like I was fudging who was hit and who wasn't.
   • I decided to add hp to the Black Spider and turn him into a 'paragon monster'. As the final boss, I didn't want him going down in just two good hits, so I decided to give him two separate hit point pools of 37 hp each - when he went down the first time he 'regenerated' into a more dangerous final form (two turns per round) which really appealed to my players, familiar with boss fights in pc games, and made the Black Spider feel appreciably different to any boss they'd faced before.

2. What approaches have you used successfully in your own game to make the final encounter with The Black Spider feel balanced against a larger sized party?

   • As mentioned above, I added extra hp to try and slightly balance out the action economy.
   • I added two extra giant spider minions (bringing the total to six). Having as many spider minions as PCs definitely added to the drama and the spectacle but if the rolls had been more on my side this could have been a bit too much.
   • We used milestone levelling, so I decided to keep the party at level 4 for this fight. Fifth level would have removed a lot of the danger, half of the party would have gained Extra Attack, not to mention the extra HP, spells and proficiency bonus increase.
   • I treated the Black Spider as a fifth level caster (as opposed to fourth level), so that he rolled a second damage die for his cantrips.

3. What would I do differently if I did it again?

   • The Black Spider is fairly toothless once all of his minions have been killed as most of his spells are crowd control, rather than damage dealing (only cantrips and magic missile, melee a last resort). If I was redoing this fight I think I'd give him the option of one scroll of fireball, to be used if the fight was going too quickly south.
   • Make better use of webbing as difficult terrain in order to crowd control the PCs.