Okay;
Here's one that I thought of just a few days ago. Dover press or other Printers sometimes put out books in "H.O." and "N". Pre-colored and easy to work with. Yes, this is heavier paper. But here's the trick. For intact buildings they work well when coupled with Tichy Train Goup Windows and Doors and Evergreen textured sheet. You can use the buildings as patterned, or as I have, they are, the base structure detailed with Tichy Windows and Balsa wood or Plastic strips.
I'd decided to throw this in after deciding it was a cheap and good tip!The buildings are well printed and have a lot going for them as to helping you figure out texture you can use. Model RailRoad stores have detail sheets of Bricks, Shingles, etc. that are paper thin and make excellent overlay material. This way You don't have to Create, Draw and Cut out Plastic for a building. Just use these as a pattern or the basis for your needs.