Dave,
Great stuff! I spent some time in the 90's exploring between Lake Mary & Mormon Lake when I camped at the Pine Grove Campground. There were two grades there: one to the west of the campground which was a logging grade that was probably what you were following, and an older grade to the east that cut across the access road to the campground. I think the eastern grade was the Arizona Central. You could find unusual spikes here and there and you could follow it until it disappeared into Lake Mary's southern shore. South of the campground access road a grade cut over from the logging ROW and bisected the older grade, extending almost to Lake Mary road. I've always wanted to go back and explore some more...