Hi EDieter and welcome to UM.

..Here's a little bit I found on Parallel Forest, also known as Medicine Park. There is supposingly an altar by the river inside the forest on the rock right next to the altar. When you are there you feel disembodied people run by, Americans hollering and old war drums beating..Also at Fort Sill is Geronomo's Grave (which I'm sure you know about). The story goes that he rises out of his grave and sits on his tombstone.

If you go to google, you'll probably find a ton of stories, so good luck...