That tutorial does look helpful, thank you. I'll get a copy of that book, it looks pretty neat.

So far, I've discovered one helpful thing... Originally I was positioning the character at the beginning of the walk path and then keyframing the whole body at the end. Very simple. I found that it looks more realistic if I move the body back a little bit while the down foot is in contact with the ground so that it doesn't appear to slide. It's tricky to keep it from looking jerky, and it's tedious as all get-out, but it does seem to improve the realism. Using a bezier tweener seems to help.