This cave is on the right side of the map south of Carter Dam near the Hunter's Blind.Д¬ache #2 - The note can be found in one of the lake cabins on the SE side of Mystery Lake.

You can find the cache for this note in Alan's Cave. When you come into the room where the first aid locker is, it is on the right from the door in the corner on a desk. The note is on the second floor in the offices. Keep in mind that this area of the Mountain Town map has changed since the Redux update.Д¬ache #1 - You can find the note inside of the Carter Dam. You can find the cache for this note inside of the cave that is directly behind the radio tower. The cache can be found behind the church area behind a fallen tree.Д¬ache #3 - The note for this cache is found inside of a house at the edge of Milton on top of a large hill. It is behind one of the houses between Greymother's house and the gas station.Д¬ache #2 - This note is found inside of a blue car in Milton on the way to the gas station from Greymother's house. Look down and you will see a note sticking out of the chimney that will inform you of the first cache location. At the back of the building there is a chimney. Those caches have an achievement of their own.Д¬ache #1 - There is a burned down school a couple houses down from the back of the bank in Milton. I can also confirm that the forest talker caches do NOT affect this achievement. You must find the note before you can locate the cache. I have had problems with caches not appearing on the map because I did not take the note with me. When finding the notes for the caches, you should always read them AND pick them up.

Forest talker supply cache