Lewiston is the town where I've actually examined this question. The first thing to remember is the "town" itself was a lot more compact than it is now.

The "center" of the town in 1840ish was Haymarket square, which is the intersection of Main and Lisbon streets. It was exactly what the name says, a market square where farmers came and sold hay for the horses of people who lived in town. From that spot, the "town" was a mile or less up the roads in either direction, up river along Main or down river along Canal street. That area encompassed the mills, housing for the people working in them, and the services they needed for their lives. Easy walking distance.

If you worked in the mills, you either walked or used the trolley.