Do you not run out of room in your satchel quicker as you progress and then require crafting bigger satchels?
I finished the main story without a satchel upgrade. You get a full size one at the end (99 max stacks).
I have a question about stocking the camp with food ,
is this my responsibility, I don't like having to hunt for the camp all the time, I have just been using the ledger to restock the food but Im not sure if I can keep doing that.
Donating to the camp doesn't have any bearing on the story. You can donate as much or as little as you like. I used the ledger to restock when it was low. The only thing worth upgrading is for the fast travel and potentially the horse stable, so you can duplicate pelts for easier crafting