To answer your first question: A very basic overview of the recursive contents of the current directory can be found with find
:
mtak@frisbee:~/Documents/vagrant$ find . . ./.vagrant ./.vagrant/machines ./.vagrant/machines/default ./.vagrant/machines/default/virtualbox ./precise32 ./precise32/Vagrantfile ./BuildRaring ./BuildRaring/Vagrantfile ./BuildRaring/.vagrant ./BuildRaring/.vagrant/machines ./BuildRaring/.vagrant/machines/default ./BuildRaring/.vagrant/machines/default/virtualbox ./BuildRaring/bootstrap.sh
It's not NERDTree, but it's a start. You could also take a look at Midnight Commander: