I believe now that the IAC, as you say, is one of the problems. The truck sat at a restaurant here for a week and a half at least, so I finally gave in and went to look.
Cranked the truck, started fine, died after 90 seconds. Tried to crank it again, no start. I unplugged the IAC, and the truck fired right up. The idle was hunting, but at least the truck was running. Not to mention, the engine seemed to have more power (dunno if that's true or not). I drove the truck about 10 - 15 miles at highway speeds. After about 9 miles, the truck died on me again, with no restart. Pulled over, plugged in the IAC, cranked once, unplugged again, and it fired up.
During the rest of the way to his house, i started to notice a correlation between the torque convertor lockup and engine stall. One time when it appeared to die after clunking into 3rd or O/D (not sure which), I slowed down and put the selector in "2" and the engine had power again without having to restart it....... weird, eh?