The hitch itself is on a bar that replaces the one between the back of the saddle bags. This is reinforced by heavy 'L'-shaped plates that connect to the bottom of the saddle bag mounts.
You can also see my wire routing choice along the backrest rail and down the bag mount. In the second picture, you can see the rear view. I elected to wire the LED license bracket to a trailer plug so that when I'm not using the trailer, I connect the harness to the LED license plate so it stays out of the way, capped off, and sealed. I made a couple of small 'L' brackets which are captured by the longer bolt at the rear by the hitch brace. On the right, I zip tied the cable as you can see above, on the left I attached the License Plate coupler.
And yes, the bike is dirty. I live on a gravel road. The mudflap is to protect the trailer from gravel. it is cut down from a generic pickup mudflap.