what are some important jobs that would accompany the settlement of a wild and unsettled frontier region?

Some important jobs would be:

Farmers: if the region is fertile enough, farmers are crucial, simply because they produce most of the food that will be consumed in the area.Law enforcers: any area needs some form of law-enforcement, no matter how anarchic it is.Doctors: some medical practitioners are also needed, in order to tend the sick and wounded.Merchants: a few merchants are also needed, in order to help with the importing and exporting of goods (trade).