D&D 5E Homebrew exhaustion/Madness mechanics for starting Out of the Abyss [minor spoilers]

[woonga]

I'm preparing to start running Out of the Abyss with one of my groups, and have been thinking about how to implement two gameplay mechanics that seem like they will be core to (at least the first half of) the campaign: 1) madness and 2) the Drow hunting party chase

I want these to be meaningful without just being something else to track, and wasn't really happy with how they were presented in the book. This is still a work in progress, but so far I've come up with the following solution:

• Each PC will receive two different colored: one to track sanity/madness, and one to track exhaustion from the drow chase
• At the start of the campaign, before waking up in the drow prison outpost, each player will roll the sanity d6 and subtract their CON modifier (or WIS, still TBD) to determine starting sanity (based on the events of their capture and some dreams they will have foreshadowing the demon lords).
• All PCs will start with their exhaustion/chase with a face value of 1.
• Certain events (such as the drow torture, exposure to the demon lords, other horrifying events) will have a chance increase the sanity die face value by +X (often accompanied by a check to see how the PC handles it mentally). When the face value of the sanity die hits 6, the PC suffers escalating madness (first a short term madness, then long-term, then permanent).
• Travelling to escape the drow will result in +1 increase to the face value of the exhaustion die per day of travel, roughly based on the distances in the campaign book. A PC can attempt to forage (rather than staying at camp for extra rest) by taking +1 to the face value of their exhaustion die. If a PC has food/water and a long rest, they can decrease the face value of their exhaustion die.
• If the exhaustion die reaches 6, the PC gains a level of exhaustion per the rules in the PHB.
• If the party is overly conservative and slows their travel trying to avoid exhaustion, it may force an encounter with the Drow hunting party. I will play this by ear rather than keep it to a strict tracking mechanic.

Any feedback from those who have run (or have considered running) the adventure? I think this gives a fairly streamlined way to turn the mechanics into some light resource management that gives the characters meaningful decisions, but also plays into the narrative themes of fighting off the madness and outrunning their former captors. Open to suggestions on how to improve this further!