Right now I'm just trying to remove dead stuff. I hope that before the
vines start growing in the spring I can prune at least some of them
properly. I'm faced with a mess of trunks and canes of all sizes and
ages, and I'm having trouble figuring out how to start.

I've got a couple of specific questions.

First, how can I identify first-year growth, so that I can follow my
book's instructions to leave a controlled number of first-year canes
on each vine?

Second, how should I deal a couple of locations where the vines died?
I must decide whether replant in the same places or not, and if so,
what to plant and how. Saying that the vines died of neglect is
probably true, but not useful. All of the vines were neglected, but
some died while others thrived. Maybe the dead vines' locations were
bad. (For example, one was next the corner of a shed where it probably
got much less direct sun than most of the others, especially in early
spring and late fall.) Maybe the vines that were planted (now
unidentifiable) were inappropriate for the location. Maybe the soil
was bad. Or maybe it was a combination of those things and others.

Beyond that, I'm looking for any sort of advice on how to proceed.