I was mainly using the diffuse , good example of conservative texturing ;p I'm wary of adding too much contrast into the diffuse and increasing repetition. I'm considering some subtle discolouration through the shader.
looks great! i love how you fit the interior into the cart without it looking too claustrophobic. However, many of ur textures seem to only be using a simple detail patter for material def, and a layering of ur baked maps. For example, the seat cushion textures could use some fade, light wear and tear... that sort of thing.