I spent last week up in Alaska for work. It is always interesting up there if you are into planes, as there are lots of old transport planes still being used as freighters, as well as all kinds of planes with skis, floats, or tundra tires.
Lots of DC-2's, -3's, and -7's still see use. The DC-7 is the preferred freighter for getting in and out of gravel strips. Unfortunately, the supply of spare parts will run out by the end of this year, and for every hour of flying, there is twelve hours of maintenance!