As an exercise in textually navigating the site I have logged on in my antique lynx browser to see if I can comment as well...
It understands CSS, so it can show HN in its full orangeness :) Also, it has color contrast correction by default, so downvoted comments are readable.
(If you enable JS, even thread collapsing works. But JS breaks upvoting, because images are not supported yet and JS-enabled HN upvoting is implemented using the Image constructor.)
w3m also works well with HN, but you have to enable images for comment nesting to work. (Otherwise it ignores the spacer gifs.)