Try this with the jumper cables... (but be careful)

Positive jumper cable to (+) battery post.
Negative jumper cable to a good metal part of the body. Like maybe where your negative battery cable is bolted to the fender. If that gives you the lights & dashboard, then you've isolated the problem to your negative battery cable.

If that still doesn't give power inside the car, then something else is going on. Fuses?

You might also try the (+) jumper cable to clamp on where the (+) cable attaches to the fusebox. But that might be difficult because it probably won't have a big metal lug where you can clamp the jumper cable.

 

Thanks Jim and everyone else for all yr help. I broke down and got it towed because I've got a torn muscle and can't be up and about a ton right now. Thems the breaks!