CrudRunner, forgive me as I haven't read each of your update posts, so you may have done this already.
My best guess is you have a combined issue between a bad battery and a bad starter. A bad battery can wreak havoc on electrical systems, including your starter, but also the electrical components that keep the truck running.
You could also have a bad starter along with the battery. Have you tried doing the hammer/tap test while cranking? Easy way to confirm. If you do have a bad starter, it's more than likely the internal components. Dealership sells the components kit for surprisingly cheap and it's easy to install. Unbolt the housing, unbolt the housing shell, slide in/out old and new components. Way cheaper if you have to replace that starter.
I had an issue several months ago of intermittent starting issues. We replaced the starter, the components kit, etc. Turned out it was the battery, but we put all that other work in too. Haven't had a problem since.