EDIT: I've always wondered why more private companies don't create shared buses to help backpackers hit the entrance to the park. A lot of the times just getting to the entrance is what makes folks use their cars, and if you could park in a nearby town and take a shuttle in and start your backpacking that would go a long way. I know some parks run shuttles inside the park but I'm talking about a more backpacker/cyclist specific transport just to the entrance to minimize impact on the park itself.