I picked up some oil colors today, and moved to doing panel lining and some additional grime. It came out well, I think. I'll get some pics of that stage after it dries.
And to the left we have a picture of the new terrain piece. I used my airbrush to do the base rust layer, then worn effects, and finally the VAC Dark Yellow final layer. Then I did the paint chipping and rust/grim work with the AK interactive enamels. I just need to seal it with a dull coat of some kind.