You do not have to install the second floor staircase in order to add more walls to the dollhouse. Their placement will not interfere with the second floor staircase installation. Adding more walls now, will help you be able to begin finishing rooms while you work on the foyer and second floor staircase installation process.
I went ahead and installed PARTITIONS #4 and #5. They are extremely easy to install because this side of the dollhouse has plenty of leeway, since the right wall has not been installed yet. No tabs had to be cut and placement of these partitions did not require a mallet. These partitions will not take away any access from the second floor. You can access all rooms for finishing, with the partition in place.
I then installed the right wall, all the tower walls and the back wall. Glue everything with tacky glue and then run wood glue along all joints. Clamp with masking tape and let dry. While you continue working on the foyer and kitchen sections, these walls will be drying and be ready for you when you're ready to work on them.
