Getting up the nerve to tackle A/C, need to remove the old

[dmjlambert]

I have a 1969 Chevrolet CST/10 with original A/C and heat, 350 cubic inch engine and TH400 automatic transmission. The heater works, and the A/C has worked but doesn't hold refrigerant. The ducts have had modifications by the previous owner to accommodate broken levers in the controller and to accommodate re-routing flexible ducts because of a larger than normal radio. The result is the levers do not successfully switch between A/C outlets, heater outlet, and defrost. Instead, air blows out of everywhere for regardless of function (heat, A/C, defrost).

I have tried investigating the diverters with most components in the truck, by removing the S-box and looking at the cold/hot flap and heat/defrost flap and their connection to the controller, and although the controller moves the flaps some and the flaps do not appear to have anything broken, I was not really able to figure out why the setup does not divert the air properly in those cramped quarters, so I think it may be best to give it a closer look and clean up while removed.

My plan is to:
A. Remove all components the A/C and heat system,
B. Send the evaporator/blower unit out for restoration,
C. Replace all under hood components with a stage-3 kit from Original Air, this amounts to evaporator, condenser, compressor and compressor bracket, hoses, and the other components that refrigerant passes through, blower motor and fan. So, all under hood stuff will be new except evaporator box, which will be restored.
D. In the cab, remove the heater box and outlets, diverters, ducts.
E. Clean, inspect, repair or replace what is necessary, test, paint, and re-install.
I have already replaced the controller with a stock-type reproduction from Classic Industries, but I will remove it and use it to test the diverter on the bench, and I need access to the radio area anyway because I'll be putting a regular AM radio in there and new center vent, and while I'm at it, re-cover the dash pad.

Here are my questions, please:
1. What is the order of disassembly?
2. Can the inside-the cab components be removed first by just disconnecting the heater hoses and the rest of the unbolting is done from inside the cab?
3. Or do I need to first remove the inner passenger fender and hood and remove the evaporator box assembly in order to gain access to removing the cab's heater box?
4. I plan to remove the engine to do some work unrelated to the A/C in the engine compartment, but that is really a separate project. Would working on the A/C in the area of the evaporator box be significantly easier to do while the engine is out?
5. If I want to use the truck while the A/C and heater components are removed, how do I bypass the heater core?
6. The hoses going to the heater core are 5/8 and 3/4; do I force the 5/8 hose onto the too-big 3/4 fitting on the water pump, or do I fit the 3/4 hose over the too-small 5/8 fitting on the intake manifold and tighten it down with a hose clamp? Or do something else?
7. The heater core may be original and is not leaking and the heater works. The truck sat in a field from 1985 to 2014 when I received the truck, and the coolant was full, clean and green when I drained it after those years sitting. Is replacing the heater core recommended anyway? I'm just wondering if my old heater core is better than a new Chinese made one.
8. Any comments about my plan?