I have seen one mountain lion (couger, catamount), turned a sharp corner on the AT in Shenandoah and he/she was about twenty yards away. Was so surprised I didn't remember not to look it in the eye, but it was gone in seconds. Beautiful critter! They are very rare these days in the east, even in areas they once frequented. Like others, I've seen quite a few bobcats and some bear, but almost always as a bit of fur, going very fast the other way. They've never worried me (though I am very careful with food).

As for noises outside, I don't use a tent, but still have the rustling problem. Typically I do not sleep all that well the first couple of nights out. But I've noticed that the longer I'm out the smaller the likely source of those noises seems to be. The first night, they are moose or bear, by the third or fourth night, field mice seem more likely. Never felt the need to actually do anything about it. Once in a while when it really bugs me I'll pound the ground and yell, but any effect is momentary.

best, jcp