"(and from the 24-point check:)
- Center bearing on driveshaft noisy.
- Valve cover gasket and "Ing Dist Seals" need attention.
- Right windscreen washer doesn't work.
- Broken light warning light on.
- Front strut rod bushings, shifter bushing, and rear diff bushing worn/torn/split."

That's all? You found a good one! These are basic wear-and-tear items for a 700 series of this age. Nothing particular to the 780, even.

Basically, you are looking at a new center carrier bearing, a new tailshaft bushing at the rear of the transmission (a good opportunity to replace kick down cable and flush the ATF), and some minor suspension work. The "rear diff bushing" is probably what we call a "torque rod bushing" on the BB. I am not sure what the mechanic means by "strut rod bushing." There is a strut mount that should be replaced with each of the front struts. The only other thing that comes to mind is the cone bushings, an easy repair.

Oh yeah....the distributor seals. Have the mechanic clean out the PCV system at the same time.

What is the condition of the fuel injection wiring harness?

I would offer $2000, but then I am part Scotch.