Unfortunately for us, I think you will find that National Parks are moving toward the point where they are not going to entertain the idea of anyone walking off trail AT ALL.  I have lived here on Mount Desert Island for 30 years now, surrounded by Acadia National Park.  When I first moved here my husband and I did a lot of walking in the park and you could barely see any signs of people having been in a particular spot, other than the (at that time) fairly small trails.  If you were on a trail that followed near the shore, it was no big deal to, nor do I believe at the time you would have been reprimanded for detouring off the path to go down to the shore.  Thirty years later, and many , many millions of visitors later, the paths are big and wide, the erosion next to paths is considerable, the roots of trees are totally uncovered from the millions of feet that have walked over them, the land between the path and the shore is totally barren of plant life.  Now, this lovely park has signs everywhere telling people to keep on the paths.  For a resident of the area, it is a truly sad development.  And while I absolutely LOVE the sport of letterboxing, and enjoy searching for boxes,  I can also understand, even though as a letterboxer I don't like them, the restrictions in the National Parks.  Though the majority of letterboxers are very careful of the environment surrounding a box, there are plenty of others who are not.  I have gone searching for boxes where it has been evident that people had preceded me, just by the trampling of vegetation that was evident in the area.

I apologize for the length of this.  And I don't have any answers.  I guess I just needed to point out that our park officials, who are so often cast as the evil ones in discussions on this board, are simply trying to keep something left of our parks for future generations to enjoy.  As fewer people have the good fortune to live in rural and/or coastal areas, our National Parks become even more attractive and see more visitors.  My park, Acadia, is now working on strategies to try to lessen the negative impact of the high numbers of visitors we see each summer. 

I guess my bottom line is this:  we all need to do our best to be careful, thoughtful and respectful letterboxers,  and to understand that while the park service employees seem like the bad guys at times,  they ARE trying to preserve these beautiful spots for all of us to enjoy.  (And no - I am not married nor related to any National Park employees!)

Memlili