Wow, thanks.
There are several B737-200s operating in northern Canada, because of the gravel runway kit that apparently only exists for the -200.
Most probably are the Convertibles, cargo-pax configuration.
Destinations may include Cambridge Bay, Resolute Bay, and resource sites such as diamond mines.
B737s because they are fast compared to prop aircraft. (Herc is fairly fast at medium altitudes but not certified for pax, L188 Electra fairly fast at medium altitudes but not desirable (some still fighting forest fires, Airspray of Edmonton has 14, but jets win by going high and fast.)