So after many weeks of diagnostics and several trips to several part stores, my truck is finally producing an acceptable amount of voltage. It settled out after this photo and running the truck for about 35 minutes to about 14.2 volts. I am happy with that.
It started with me hooking up the fifth wheel, about to make a short trip and noticed that I was no longer producing electricity. I proceeded to check things out and then replaced the alternator. This of course did not fix the issue. As it turns out, all the voltage regulation is run through the computer. I tried to buy a new one of those which would have cost me $500 but nobody had them or would sell me one.
So I finally decided to go completely DYI and externalize the voltage regulator to its own device. I got that all hooked up and I was getting too many pixies with it, around 15.7 volts. I didn't want to just boil my batteries to nothing. So after running a separate power lead and doing some additional rewiring, none of which I am very proud of and will not take a photo of, I got it all back together and working "properly”. I can at least move on to other projects now.