2020-09-19: at this point, the truck is home, and other than fixing a few lights that didn't work (corroded contacts), it is so far untouched, but that is soon to change, as it needs a lot of work. more to come...
2020-09-20: Symptom: fuel gauge stays a little below empty, but low fuel light works as normal.
Dropped fuel tank and checked sending unit, which seemed to test out fine. at this time i noticed low fuel light changed, depending on sending unit position. then i pulled the gauge cluster, and checked the solder joints as they have been known to crack. looked fine under magnification, so i can only assume the gauge stepper motor is at fault. i ordered a used one, as it was cheaper than a NOS one. hopefully it works. I also ordered a pair of fuel tank straps, as i had to cut one to release the bolt. other was looking a bit fragile as well. ordered a replacement fuel door (OEM was rusted), and a passenger window motor at the same time as the tank straps. Rock Auto
2020-09-26: i re-hung the fuel tank, replaced the passenger window motor, fuel door (primed, not yet painted), and installed the fuel gauge stepper motor. it still reads low fuel, but the fuel is low, so... i don't know yet. noticed the fuel filler neck was rotted through, so i removed it and ordered a new one from Rock Auto.
2020-10-03: the fuel filler neck is installed, and the brakes are bleed. i had to replace the front calipers, but i have brakes now!