Trey, I don’t know if you know, but you’ve basically reinvented dirtrack.el. It should be included with your Emacs distribution. See myrecentposts on the topic.
Now that I look at dirtrack, I think I prefer the implementation on my post – only because I don’t want the full path in my prompt (b/c it often gets very deep). Perhaps I’ll see if I can patch dirtrack to do what I want…
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