Love the support for the Exploration pillar, and the encouragement for DMs to think in degrees of success. A couple points, if I may.
First, I'm curious what you're assuming adventurers are doing when they're using these rules. If it's traveling between towns (as in most of the examples), that's not really exploration (i.e., mapping new areas or making discoveries); it's logistics. Which, at least for me, is less engaging even if it's punctuated by interesting challenges. Maybe I just need to look forward to hearing more about those journey rules, in due time.
Second, How many supplies would you expect a typical well-prepared adventuring party to have when, say, they're starting off on a journey? I ask because the "Pests" challenge says on a failure you lose 1d4 supplies, and on a Critical Failure you lose half of your remaining supplies. This can create two weird outcomes. In the first, if I have two supplies when the pests descend upon them, then three quarters of possible Failure rolls (2, 3, and 4 on a d4) are worse than a Critical Failure. That seems wonky narratively and mathematically. In the second weird case, it means a Critical Failure is worse the better provisioned you are for the trip. Like, if my party brings 40 supply, they lose 20. If they bring 4 supply, they lose 2. If supply is sort of "exploration hitpoints," that's analogous to an attack that deals more damage the more hitpoints you have. Some spells work sort of like this, but they're usually wrapped in flavor I don't see here.
Maybe these are both intentional? Just curious what the thinking is.