Would you believe making the trailer doors, the canopy and everything else was really simple. But roofs! Oh man! That thing kicked my keister! I did eventually find a very simple way to make a roof. But that's the building which is a building I found on the route I'm doing currently and is a lot like a buiding that I saw on Chris's site.
You may wonder why I haven't done the roofs yet. The reason is that's the easy, very easy stuff to texture in Sketchup. What hit me as I was texturing the outside walls of the building was I didn't know a way to take part of a texture and apply it to say a poly meant for a door. Fortunately there are a ton of video tutorials for Sketchup you can watch online and having done it, you can see I got doors applied to the right places and so forth on the building.
Don't rush out and try learning Sketchup just for viewing this. There are a couple of caveats that need to be worked out first. If you know the answer to these, please, help us out here.
1) Will the free version export textures? From what I hear, doesn't sound like it does.
2) Will the Pro version export textures? Sounds like that could work if you export in 3DMax format. The Pro version is $500.
3) One way I figure to lower the poly count is to only use Sketchup for parts that need Boolean operations like subtraction then import into 3D Canvas. In Sketchup, using the push-pull feature makes subtraction so easy and safe to do. No worries over how many doors/windows 'whatever' you add to a surface (With 3D Canvas when I go to do subtraction I have a full bottle of aspirin near me at all times.).
Anyway... checkin' it out!

Rich