Just splice into the rear lights (read solder and tape). Use LED's in the portable towed lights and you'll be great! I used two sets since my bus is wired with one light for stop/running, and the other for turn/running. It works great, they magnetically mount on the top of my towed trunk, and are very bright. Good Luck, TomC
Tom,
If you aren't careful you are gonna be roasted on a spit and basted with 15W40 for suggesting that someone use a solder joint instead of a crimp (crap) connector.

How dare you to not follow the herd!
I was brought up a long time ago, We seldom if ever used a crimp connection, even including battery terminals. After all, when you buy a premade battery cable it usually has a ring terminal on one end and a lead battery terminal on the other. Under very few circumstances have I ever seen lead terminals or soldered connections melt, however, I HAVE seen a whole bunch of crimp connections, including the high dollar, factory connections come loose.
You need to rend your clothing and pull your hair all the while screaming Mea Culpas and asking forgiveness!
Dallas