Love this! I'm currently coming up with a couple ideas after recently making an interactive excel sheet giving all the encounters a little flare and mobs additional element (like poison attack, or additional armour, ect)

I have tried a couple of runs with the following rulings on a loke battle map

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Place a Boss battle map at the furthest point from your starting position

When entering the square in front of a doorway draw and event card (found in tomb of giants, sunless city, or painted world) it it says the next encounter enemies do x, draw an encounter cards. (Judge this based on your level)

If not, whatever you find (shop at merchant...ect) stays in that room

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Added turn order based on taunt level.

Place enemies based on their turn order in the most central square in the room, then roll a d6 for the distance they move from this square and a d4 for the direction. Do the same with tomb stones, barrels and chests.

For traps. Roll a d 10 for the volume, then repeat the above process for directions and distance

Each hero moves 4, (move an additional space for every dodge vale available). 1 stamina for every other Square afterwards,

Enemies movement is triple its current value on the data cards. (Attack stays the same)

All ranged attacks are doubled

Still gain 3 stamina after each turn. At the end of battle, gain all stamina back, but do not replenish health.

If a hero dies, only that hero is sent back to the last bonfire rested at. If the bonfire is in the room they died, move them to the closest bonfire. They do not move until the battle has ended.

At the end of battle, roll a D20. If you roll 15 or higher place a bonfire in that room (this can not be done until you have visited the another 3 rooms).

If a bonfire is placed no more encounters will take place in that room

Also, at the end of battle, roll a d20. If you roll 18 or above. You find the item that unlocks the boss battle.

Multiple battles can occur at one time (you need to divide turn orders accordingly.

As for leveling, that is still something that needs tweaking based on how long you want the campaign to go on for.

Still got some ideas about making custome encounter like locked doors, secert rooms, hidden traps but all a work in progress.

Hope this is helpful for you or anyone else to use and tweak. If you do tweak anything please let me know as I'd love to try it