This post shows the addition of the stairs and various painting stages. Some old log chunks have been created to fit the holes in the face of the building. You can see the foam showing through areas where I have cut back to add more or different detail or larger structures such as the stairs. Changing and adding detail and even changing the basic shape is very simple. Wood putty can act as coverage and glue. A simple utility knife does most of the work at this stage.
Roughing up of surfaces before application of glue or wood putty is simply a necessity. Toothpicks between pieces is dependent on sizing. Large and very small pieces tend to get toothpick support. I do have a tendency to overbuild supporting structures.