To put the depth of the crater into perspective, the Perrine Bridge in Twin Falls is only about 180 feet taller when comparing the blast site's floor to the rim. The oldest known crater in Idaho was caused by an asteroid 600 million years ago and shares a border with Montana.
I am in the process of trying to find some places to explore backpacking. I found some places that I believe would be a good start for me and other beginners. If you can think of any more please let us know. I think I am going to have to try a few of these out when it isn't too hot out though.