A two hour test drive revealed a few issues.
The air conditioning blows cold although the air flow could be improved. It has also produced a chemical smell from day one. It is an aftermarket unit added by the RV maker that built the box so everything is crammed under the dashboard. The outboard vents produce 50°F air from a background of 100°F along the firewall. Not bad, but insulation along the roasting cab floor and up the firewall would really help. Future project! The problem with the system that had to be addressed was the smoke coming up from the back of the AC control panel. A quick look at the back of the panel revealed a corroded power supply wire that had slowly burned away its insulation and finally broke off completely. Soldered on a new connector and used heat shrink tubing to make it sealed. No idea how a California truck stored for years gets a single corroded connector, but it does set minds awandering... Works great and no more chemical smell as the insulation slowly burns off.
The second issue is a result of the aftermarket AC as well. The truck came with a 60 amp alternator which is limited with the running lights and headlights, and AC fan running on high. In fact the fan speed drops when the full lights are put on. At idle the ammeter is showing a discharge. All the alternator juice comes through a spindly 10 gauge wire. If the 100 amp alternator had been specified the idle output would have been better and the wire would have been 8 gauge. I want to put a modern alternator with a serpentine belt in it. Future project. The wiring harness will need some upgrading as well. Chrysler's rocket scientist designers run the entire alternator output through the ammeter in the dash. Eventually the corrosion steps in and destroys its connections. Very common to have an old Dodge stop dead in its tracks with absolutely no electrics at all. I'll put in a shunt style ammeter as a future project. The connection looks good for now. An inspection did reveal the connection at the back of the alternator was corroded. Same as the AC power wire.
I replaced the first 16 inches of the 10 ga wire with 8 ga wire. I also spliced in a new 8 ga wire to help feed the battery directly. Sadly with it hooked up the ammeter won't show a charge only a discharge, but the battery charging voltage is up by half a volt. Obviously the factory harness is a restriction.
All the connectors used were soldered in copper with heat shrink tubing over the connections. Take that Chrysler!
Photos are alternator factory connector, new added battery feed connector, and comparison of factory 10 ga feed cable versus new 8 ga cable.