I can tell you that both Dog Mountain letterboxes are alive and well.
My mate and I nabbed them last month. Ryan Carpenter has one up there
that is part of his African Safari Series and Funhog has a Dog Mountain
Box. There are also two Eagle Creek Letterboxes, though I have not
achieved either of them. One is Ryan's (also of said African Safari)
and the other is Funhog's as well. Have a great time!

Best regards,

Amanda Briles
The Paisley Orca