Notice these two corner trims on the Beacon Hill. They weren’t there before because the kit just didn’t bring enough to cover these two areas. I believe it's because these two areas did not really need to be covered since they are away from view. I really wanted to put trim on them. I thought about buying 1/8th" foam core but decided that it would be a waste of money to buy a big sheet for just two small squares.
I used cardboard instead and cut out my pieces by making a template on paper of a piece that was already on the dollhouse. I then painted my cardboard pieces and glued them in place. You would never know they were not wood.
I used fabric trim to make crown moulding. It is a very inexpensive way to make fancy trim for your ceilings. These decorative fabric ribbons come in a variety of sizes and designs. They are available at any fabric store and you just have them cut to the amount of yards needed. When painted, they look just like fancy miniature crown moulding at a fraction of the cost. The best thing about these fabric trims is that they are very easy to cut and shape to fit around any type of angle or curve. I did not paint mine for this dollhouse.