I ran a silver Sharpie around the edges of the rear doors and hinges, and used red and white Sharpies to colour the tail light lenses. A little black grime is streaking down the trailer sides and roof, and a few old boards and stuff have been cast underneath.
As for the building itself, I thought I'd identify it as a closed down bar or something like that, which should fit right in with the "neighborhood". Of course the place should have a name. One of my nicknames, "Jimbo" came to mind, so I googled "Jimbos signs photos" and a bunch of them popped right up on the screen. I chose a couple of signs that I liked, straightened and cropped them in Paintshop, and printed them out.
A little careful trimming with an Xacto knife and some Super77 adhesive later and my signs are done and attached to the exterior of the bar. I did the same with the Parking and Miller High Life sign. I used that one to cover over the Pepsi decal that I had put on the side wall years ago. I'm not really a Pepsi drinker anyway.
With 813 switching in the background, here's the view of the rear of the building, which is what is most easily seen on the layout.