RUSA has added a provision in its Permanents rules to allow you to start and finish your ride at a location other than a checkpoint (if the perm route finishes where it starts). Here is the new wording (highlighted):
Ride Direction and Starting Checkpoint Options - Permanent routes may be ridden in reverse direction. The rider must determine that the reverse route is safe and legal, and revise the route if necessary to make it so (for example, to avoid riding the wrong way on a one-way street). For a permanent route that starts and finishes at the same location, the rider may (1) start and finish the permanent at an intermediate checkpoint or (2) start at any location, proceed to a checkpoint, traverse the other checkpoints in their order on the route, and return to the original starting location. In the case of #2, the rider must document the start and finish location in a manner described in Article 8, providing timed proof of passage for both starting and finishing.