Journal articles are probably the best way to learn about a town's occupations and history. What's better than a detailed article with lots of sources and description on just your subject? If you're researching a small town, it almost never happens - except in Killingly.
The Killingly Historical Society has a nice collection of online journals, dating back to 1997. Each covers aspects of town history, profiles of famous people, and more. Many sections are excerpted from other sources, but others are written by locals. Happy reading!