2 Books Found

Based on your description:

"the title was something like "make your own kingdom" or "make your own country"; it was an imagination-inspiring book, guiding the child reader to create an imaginary country: creating a map based on their own bedroom, creating a miniature capitol city with blocks, maybe designing the country's seal. (So, not a story book.) It was not really educational, more purely craft/imaginative (making models of buildings, for example.) It was published before 1985."