Oscillating or Drum Floor Sander
Drum sander was the best solution. The pine boards being uneven was a big enough problem on it's own. Even with 40 grit paper on drum sander it took multiple slow passes on an angle just to get the floor flat enough to be able to sand the entire board. Oscillating sander would have taken forever.

As far as paper, 5 sheets of each grit should be plenty to refinish that amount of space. I may use closer to 10 with the lowest grit, because some of the pine floors are so uneven.