The aim here is to emulate the Unix nroff, which formats text as best it can for the screen, from the same input as the Unix typesetting program troff.
Ralph Droms (droms@bucknell.edu) has a style file and a program that provide the LaTeX equivalent of nroff, though it doesn't do a good job with tables and mathematics. The software is available in support/txt; the original dvi2tty often does an acceptable job and is available in dviware/dvi2tty
Another possibility is to use screen.sty (available as macros/latex209/contrib/misc/screen.sty). Use a dvi2tty program of some kind; you might try dviware/crudetype as well. Another possibility is to use the LaTeX-to-ASCII conversion program, l2a (support/l2a), although this is really more of a de-TeXing program.
The canonical de-TeXing program is detex (support/detex), which removes all comments and control sequences from its input before writing it to its output. Its original purpose was to prepare input for a dumb spelling checker.