Frank:

You've just got to bit the bullet, go after them, and in two yrs they will look textbook perfect. Prune out as much of that excess growth and old wood as possible while leaving at least four strong canes per plant of last years growth. With all the pruning you do this year, there will be plenty of strong canes grow this summer. The following year you will have well-positioned, new canes closer to the trunk. All the old wood will be gone.

There is no fruit more forgiving of pruning errors. If you cut them back to a bare trunk right now all you would lose is one crop. You can do it in two and have good crops every year.

You get grapes out of the first three buds from new growth at the end of each cane and spur. Commercial growers leave about 50 buds/vine, amazingly few. I'd cut out everything smaller than pencil size everywhere, then pick what you want from what's left. They don't have to be picture perfect this year, just much-reduced.