A little light weathering–brings the detail out. A light dusting on the underside highlights the details lost in shadow, and a little dirt and grime along the body emphasizes the panelwork and doors. I’d suggest using a wash for the body. Brush it on and let it settle into the cracks and corners. Wipe it (mostly) off before it dries, and you retain the glossy sheen of the paint, leaving the dull wash just in those cracks and corners. On the trucks, I’d use powders primarily, though I’d be tempted to start with a grimy brown/black wash, then dust it with the powders. That’s the approach I took on my EBT M-8 project. Well-maintained, but not stuffed-and-mounted.

Oh, and fantastic job! I’ve enjoyed following this along.
Later,
K