Add detail to boxcars with open doors.  Add some crates, boxes, tarp load, or figures to your boxcars that have open doors.  There are even lumber, barrel, or bag loads you can place into an opened boxcar.  You can even add a fake wood flooring to add more detail.

For the TL;DR - just scroll down an look at photos is useful since it's about architecture :) Feedback appreciated !

I want my layout to have a high level [ ... ]

 This is Micro trains Line SD40-2 Santa Fe model which I customized with working ditch lights.

I've finally added as much plaster cloth as I expect I'll need, and have moved on to priming the base before painting it.  Priming made it look unfamiliar, [ ... ]