I always paint my surfaces right away, no matter what the material. Bare plywood doesn't say railroad to me, and blue or pink foam is worse.
I like to paint the exposed portions of my layout to show what is going to happen in that area, and it serves to provide an undercoating at the same time.
Here, I painted the streets one color and the lots another--just to get a feel for the layout. I'm going to cut it up to install switches. I'll plater coat over that and repaint it with brick color what I'm going to have brick streets, cocrete color where the concrete where the concrete will go and grey where the asphalt will go.
I want to keep the end product in mind.
