A hunter gatherer settlement of 100 people - virtually all of which are adults, is HUGE. That's 100 gallons of water plus about 300 pounds of food per day. There's absolutely no way that this area could support a population that large. Look, I get that people hold KotB as this fantastic adventure and great example of a module, but, the truth is, it's not actually thought out. Like. At all.
I just checked. In Area B, the Orc Lair, there are 38 adult orcs in this cave alone. There are another 30 adult orcs in the next cave. There are 44 adult goblins in Area D. There are 44 adult hobgoblins in Area F. I'm going to stop counting now. There something like 200 adult humanoids in the caves. That's FAR too large for a hunter/gatherer location. There's just no way.
It's a tower of orcs. There is zero thought given to anything resembling realism or world building. It's a random collection of humanoids, most of which hate each other just as much as they hate humans, all living cheek to jowl, side by side in harmony.
The PC's don't actually have to do anything. The humanoids would all be dead in a month.