The red wire does not have anything to do with the starter. It is the black wire on the ignition switch that is the source of +12VDC for the starter solenoid through the ignition switch (purple "SOL" wire). It also provides +12VDC to the red wire on the ignition switch to power most everything else electrical on the car. As Kenton said, "Make sure the red wire is a good tight fit on the ignition switch spade terminal". By replacing the red wire on the ignition switch, your loss of electrical power problem has been corrected. As far as the starter problem, it is still probably either the solenoid/ Bendix on the starter, or the starter motor itself. The only thing inside the car that could cause the starter problem is a loose or defective purple solenoid wire on the ignition switch, or the ignition switch itself being bad/ intermittent.
I lost track. Are your ground cables correct as per OEM? One from the negative battery cable to the firewall, and the other from one of the starter bolts to the firewall? It is of paramount importance that both of the ground cables have a good connection to the firewall. The use of the correct star grounding washers is also very important.
BTW, I really like your Nomad. It is a beauty! Could you post some more photos of it?
Steve