Bill, I think your project is looking good for a first time.
The smaller and less costly 027 cars can be made to look much more detailed than they actually are, and also look better on a small layout. Here's a few of mine.
First is a former Rail Blazer set gondola (originally unpainted red plastic) that I bought from a forum member here.... El Classico I believe. The cover I made from the roof of a otherwise damaged box car. The real railroads don't waste anything either. So even 027 trains can be absolutely prototypical, at least in principle.
Next, the Procor Tank Car. Just because I'm an 027 guy doesn't mean I don't like current trains, even if the body style is just suggested. Wanting a more modern tank car, I built a frame to mimic the unibody tank car, with an 027 single dome tank body mounted on it.
Lastly a MARX flat car, with a crane from some kid's toy. Some other found items from my junk drawer and it works for me. It's more "decoration" than functional" The boom can be moved up or down, the cab turns, but the crane hook is fixed to the boom.