For a loop that long, you should create a separate sub-bus wired to the output of the auto-reverse unit. Then connect the track in the loop (and only the track in the loop) to the sub-bus with feeders. Use heavy-gauge wire for the sub-bus, just like your main bus.
It takes an iron man to play with a toy iron horse.
This is similar to advice you'd get whether you're working with standard DC or DCC. The loop needs to be electrically isolated from the lead in track on all rails. It's usually best to put insulated rail joiners on all four rails coming out of the switch that forms the loop. From there on, the loop needs to have its own buss, which is connected to the power pack (DC) through a reversing switch, or reversing module output (DCC). If no insulators are used, you'll have a dead short through the rails, and it's a short to both DC or DCC.
The auto reverse module provides the power to the reverse loop. You still wire feeders and a bus, just with the source to that section being the auto reverse module (which is powered by the controller) rather than the controller directly.
Jeff But it's a dry heat!
I think what it's saying is that the power connections to the reverse loop track have to all go thru the reverse module first, then to the track. If you have some wires going to the main bus directly it won't work.