Once the track was finished and operating I began mocking up some structures. Working in the larger scale buildings are rather easy. I mocked up the buildings with foam board. Once I was satisfied with the design of a building I used cardstock (usually from cereal boxes) to make siding, trim, shingles etc. I tend to measure very little preferring to draw a line by eye and cut out using regular ol' scissors. Parts attached mostly with elmers glue or CA if part has to dry fast. I paint mostly with acrylic artist paints as they are cheap and there are infinite color possibilities. I use them on everything - scenery, buildings, engines, rolling stock and people.
The foundation stones are made from pink construction foam just like the base of the layout. I cut strips approx 1/4 inch thick by 1/2 inch wide and tear down the center creating two stips with a ragged edge. Then break off pieces and glue in place with Elmers.
For masonry buildings I also use foam board. I get the cheap brand as the paper covering peels off easier than the good quality stuff. I peel off the outside and draw the stone or brick pattern. Then slice along the lines with an exacto followed by an old ball point pen. A little practice and the shape and texture is easy to control.
Again, some acrylic paint is applied. For this brick I painted a base coat followed by a heavy wash of white which I wiped off to leave mortar lines.
You make it all sound so simple in your description but clearly you're a master modeler. These pictures of your work are proof of that. This is easily one of the more inspiring threads on these boards.
Thank you for the favorable comments and praise. I am just an average modeler at best. Anyone can achieve this level of modeling. I have little patience so I like quick / short projects. That is why I choose such simple methods and materials. If a model takes more than a few hours over a couple days, I kinda give up om it. Throw it together fast and cover it with paint quickly.
I do not build many "foreground" models. I count on the eye taking in an entire scene rather than looking closely at an individual piece. Look closely at any of the pictures and you can quickly find many errors and things to critique.