Price of wood, plus cost of gas to go get it, whether gathered (outside the park) or bought, causes us to be very careful about the amount of wood we burn. Of course, if you need groceries, then a trip into Super 1 kills two birds with one stone.
Here's another thought, save your firewood money, drive over to Lake McDonald Lodge, get yourself a drink from the bar or mug of hot chocolate, and go park yourself in front of that big fireplace. Ahhhhhhhh, that's the life!