I've reviewed all of the posts to my thread and here is where I've ended up:
There are two basic options:
1. Cut into factory wiring, insert diodes, and use the existing tail light bulb.
2. Install an independent system which requires adding a 2nd bulb to the tail light. No cutting of the factory system. Need to drill a hole in the tail light lense.
3. Then I found this last night: Hopkins makes an integrated diode, plug-in harness
that doesn't require any cutting of the factory wiring AND uses the existing tail light bulb. Seems like the best of both options 1 & 2.
This harness came out in October, 2012.
It sure seems to make wiring your toad an easy task.
Please comment if you see any problems that I haven't.