Thanks

Painting the vehicles is really quite simple, I base coated in brown, dabbed on some orange with a sponge, then 'salted' the vehicle.
Basically I sprayed the car with water and poured on table salt, sea salt and baking soda. Once it dried it will look like this

Leave it to dry for an hour or so, then spray with your top coat using an airbrush (mine is just a cheap 10 quid Chinese airbrush from ebay)
Once dry wash away the salt with warm water and an old toothbrush and your done

You can add in some extra stains using vallejo smoke
The trailer I pretty much did the same way, but after washing away the salt and leaving to dry I weathered it with cheap dry pastels (4 quid in one of those discount book shops), Simply scrape the pastel to create a powder, dab it on with a brush and then fix it with isopropanol/rubbing alcohol (5 quid for a big bottle), just dab some on and leave it to evaporate and your pastels will stay on.
I tried out a little Decoart crackle glaze after that but at anything over 6 inches away the effect is kinda lost on the eye

It looks good close up though.

After that I just do washes with vallejo smoke