Regarding test points on a chassis, some may be for things other than voltage. For example, an RCA CTC-11 has test points where you can clip a small resistor from there to the chassis to disable a CRT gun while making adjustments like convergence.
Is it possible to reconnect everything if you set the chassis on its side behind the cabinet? Here's one of my CTC-11s.
Years ago, I did the same thing by hoisting a cabinet onto the workbench and sliding the chassis partway back in. Every connector reached, except for speaker leads, which I extended with alligator clip leads.
May sound goofy, but it's easier than building a complete set of extension cables that you may never use again.
For a chassis that won't safely stand on edge, I have used heavy metal "L" braces screwed into the chassis mounting holes.
Just some ideas.
Phil Nelson