Put in some time to make a dozen quick terrain pieces.
For forests I used some Dollar Tree Christmas trees that were just sitting in the Christmas box. They are not great looking, but they are more than functional. I would rather use model railroad trees if I can find them; they probably got thrown out.
I still need to cut some felt to match the bases, to represent the trees when a unit enters them.
The buildings are painted electrical switch boxes that come in a variety of sizes and range in price from 2-7 dollars. I did not add any details, since I am not sure exactly what they will represent. They have an added bonus of being made of hard plastic and have knocks out that can represent skylights.