... and finally to Nick's questions--now it's my turn to apologize for taking so long! But thank you very, very much for your rambling--I really enjoyed reading your thoughts.
So I'll start there: I'll talk about what my intentions were, but part of my thought is that your reading of the poem (or your "discovering" of it) is more important than what I intended--and I actually think some of your readings of my work are much more creative and smarter than whatever it was I intended. And that's the point: the poem serves as a kind of jumping-off point for other thoughts and ideas--not mine, but yours, and other readers'.
So, to answer your question about who we should write for, I guess I think that I tend to think about audience more than some other writers. I think this comes out of my undergraduate education and my work in business and business communication, where audience is everything. I'm really interested in "the reader," what the writer can know about him or her, and how the poem can somehow speak to that particular person. It's hard, clearly, since you never know exactly who's going to read the poem or book. But I don't think of a particular person (usually) to write to; instead I try to think about what is true for that person on the other end of the book: that they are holding the book, for example; that they are reading words, and so on. It has a lot to do with the physical experience of reading.
So, as far as my intention, and those footnotes, THAT's what "Cartography" is about: how does a writer really communicate with the particular person reading the poem? How does the poet NOT write "for him- or her-self"? For me, "Cartography" is about mapping the space in-between the writer and the reader, which in my thinking is the page itself. This gets back to my fascination with the page and with formal experimentation--and, I think, with seeing what a book can do that a computer (or Kindle, or iPad) can't. You can't hold individual pages on a Kindle, and you can't flip a page with the same kind of movement and physical experience on a iPad. I find those facts an interesting way of approaching the reading experience in an age when the reading experience is changing so drastically.
To return to your question, I guess the advice of "writing for yourself" has both good and bad aspects, but in the end, I want the reader to recognize that he or she is the one making the meaning at the point of reading. I didn't come up with the ideas you wrote down in your journal, you did, and in that sense there's some poem in your head that is a little bit of my poem and a whole lot of your ideas. I think that's a good way to read any poem--once the poem's published, the writer's work is mostly done (except for interviews!): everything is in the reader's hands now.
In relation to your thoughts on "The Book of In," I think, 1. that your ideas are fascinating, and that 2. they come close to what I was thinking as well, particularly in relation to the idea that "we physically become entwined and irrefutably inseparable from the things that we are 'in.'" I think I mentioned earlier that I'm really interested in how we're plopped into this life and are continually having to find our way through it. I'm no expert on Heidegger's philosophy, but I think that this comes close: the context (what we are "in") always precedes the person (in this case the "we"). We must be born into something. This also touches on (and again, I'm not an expert) Buddhist philosophy: we're born into the world, yet we think we're somehow separate from the world, like we don't need the world around us to carry on being ourselves. (Incidentally, this illusion is what leads to suffering, according what I understand of Buddhism; you can also associate this idea of the illusion of separation with what you called "some mishap," or, perhaps, the Christian notion of original sin and separation from God).
In relation to your specific question about "stitched to a page, we call it a body," I was thinking that "it" referred to the page itself, so that you could say "we call the page a body." That said, "it" could refer to something else; language has a logic that I'm not fully in control of, and you have the right to think that "it" refers to something else. That said, your general idea about the soul matches with my thought, that some incorporeal "we" is stitched to the page, or, if you want to extrapolate, to the material world.
As for your last question, when I first started really getting into poetry, I had a really hard time understanding the relationship between form and content. Ultimately I think they're inextricable, and that even poems that seem formless, or in which the poet doesn't intend any particular formal meaning, still has a formal meaning on the reader's end. I really like "reading" form. I think a good poem teaches the reader how to read it, and that "teaching" comes through most clearly through form. I also like using formal experimentation to disturb meaning into new kinds of meaning. I think this comes out of my distrust of my own ideas--taking a set of sentences or lines, as I did with "Cartography," and experimenting with them formally may lead to new, more interesting ideas. That said, the point is always toward some kind of meaning that form and content make by working together.