Well, I worked on it some more this afternoon. The right front ended up being a very unusual problem. There was power to the switches, so I decided to check the door motor. The black and green wires from the switch meet a set of black and green wires from the motor at a small junction block that clips to the door under the door panel. Once I until the screws, cleaned some waxy looking stuff off the lugs and put it all back together, it works great. I'll check the left rear later, but I suspect it's the same problem.