Pull the rubber boots off your battery cables at the battery. Tell us what you find.

We may be over thinking this but thats OK.
After the battery cables and starter connections there is a ground buss under the drivers side floor board.

I installed new battery cables and terminals (every last one of 'em!) with plenty of dielectric grease. The old terminals were pretty corroded, however, it still wouldn't start. I pulled the starter to find the pinion gear stuck in the out position and the wiring going from the solenoid to the starter fried pretty good. Now it'* got a new starter with a lifetime warranty plus new cables and terminals.

Thanks for all the help guys!

Great job you made our day!