The setting of Rodman Philbrick's Freak the Mighty is unnamed but is based on the author's former home of Portsmouth, New Hampshire, where he went to high school. It is not a rural setting, but a city or town of some size with many dangers. There are housing projects, particularly the rundown New Tenements, and roving gangs--a sure sign of urban plight. Kevin and Max live in duplexes, most often found in cities. When the two boys make their trek eastward, they walk for "miles," going through other neighborhoods before reaching the hospital. The city is a depressing place, and most of the homes and buildings are sad refuges from the danger that can be found outside. A peaceful, country setting it is not.
"Your average chunk of chainlink heaven" and the sad description of the lake the folks gather at to view the Independence Day fireworks is indeed signs of the families' lack of wealth. I see the area as more suburban, even if economically depressed. Agreeing with the above assessment of it NOT bein rural doen't rule out suburbia. There is no mention of tall city buildings. In my experience, duplexes are found more in suburbia, where they have a tendency to have some yard space. I've seen duplexes more commonly in suburbia. Finally, in cities, developers want to increase population density, and would build taller apartment buildings. My ruling is the setting is poor suburbia.