Ahh, after a hardware run for some sleeves, nuts, and bolts, followed by some bandsaw work and time on the drill press, I've got a working door slide. Next step is to get the end-stop switches mounted and adjusted.
Here is the coop door about 1-1/4" from full close. Note the latch and puck positions:
Here is the coop door closed and latched:
Here is an overall view of what I have done so far: