No, I've just driven the trails along its fence line. Half the time an old guy in a truck will mirror you for a while on the trail just inside the fence.

I do know some folks who have been in the park, both invited and uninvited.

It's nothing crazy or special, just a private hunting camp with a mountain in the middle of it. People with tiny brains will believe anything you tell them about it though. You can see it all using Google Earth, and there's not a lot going on.