One suggestion I have is to add reflective tape to the back of the trailer.

I think the narrow width of the trailers including the spacing between tail lights might make the trailer appear farther away than it is.

I think the more reflective material makes it appear brighter, which subconsciously may make it appear closer, so they will stay further back. It helps the trailer be seen quicker too.
Also the wiring does not fail or come unplugged and even works when just parked.
I have pieces of the reflective tape along the back, one white piece up the vertical fin, then pieces on the fenders, and the sides of the trailer.

http://www.etrailer.com/Trailer-Ligh...cs/RE418T.html

Chris