Migration to NH is coming more and more from MA, but they're not the big reason this state is going more Dem. People from VT and ME are also moving here, and as the native population ages, they want that "free" stuff like Medicare, etc.
Unemployment is significantly lower than the national and regional averages. Even in a modest area like mine, it's still under 6 percent. Last year, it was just above 3 percent.