Just fixed a couple hours ago and a heads up to all MTV owners! The problem had nothing to do with the alternator or regulator. There are two wire harnesses that come up from under the cab and enter the dash compartment right next to the throttle control linkage. If the wire loom doesn't come up high enough, the linkage can rub the wires and eventually wear through causing a short. One of the wires in that bundle is the hot wire to the energize side of the voltage regulator. In my case, that wire was damaged and fried. Therefore, no juice to the regulator and the resulting charging issue. Every MTV owner should remove the dash panel and check this area. Yours might be fine, but I seriously doubt mine is the only one. I also consider myself lucky. That wire is the 28V side and the short area was pretty charred with a couple other wires needing repair. It could have easily been a disaster. This was not an issue that the truck had when I got it. The chaffing may have begun, but the voltage was fine.
A few simple precautions / upgrades can prevent a mountain of headaches in the future. I will post this info elsewhere for those not following this thread.
Be well.