Mike - 

You wrote, 

"Have you noticed that you see trash along
the trail close to a trailhead (maybe for the first 1 or 2 tenths of a mile), then everything is clean after that?" 

You forgot about the Bud Light cans. They persist right into the darkest depths of uninhabited forest and desert lands. It doesn't matter wherever I am that I may think that no-one could have been within the last 50 years, than no sooner does a Bud Light can pop up. I'm beginning to think that they're dropped from the sky by planes rented by Anhaueser Busch Corp as part of a clandestine advertising campaign...

Just a humorous (and yet saddening) observation... ;)

-Mike-  (n4/c)