I agree I think that they set up the orchards and the town set themselves up on the edge of it. So the edge might reach into the city itself, but the barn, house, etc are not quite within them. I do believe they are a part of the city though because in another episode with the brothers Flim and Flam (I think that's their names) the mayor of Ponyville declared that the winner would be the supplier for all of Ponyville. This seems a little vague (sorry), but I'm trying to keep spoilers to a minimum. To me that said that they were part of Ponyville.
I know I live in a small town (IRL) and there homes and such between the next town and ours, but since we are bigger they are considered part of the town I live in. Some of them are even farms so it's pretty similar. Even though they don't live within in the town themselves they are still considered to live in the same town.