Trailer is looking great, too great for what I am used to seeing on the roads.
To get the true scale points I think it will need a bit of weathering. Once you get it painted you need to saok it down with water and warp some of the wood so the ends stick up. Then go at it with a hammer and chisel and make some holes that are just small enough that the backhoe wheel doesnt fall completely through. Then remove 2/3 of one of the diamond plate wheel covers and repace it with a couple layers of half rotten scale plywood. Finally cake a good thick layer of several different colors mud all over it. A shredded tire on a rusty rim laying on the tongue will add some extra style points.