As far as the sawzall, use your wood blade, and put a drop cloth down to catch the bullet or two of shavings. If it gets clogged, the blade can be brushed off easy enough.
As far as a burner, for bulk work, I use a witch's pot and a log fire in a pit. Stacked bricks up to hold the pot up where logs can be put underneath.
Make a day of it. Sit upwind, drink beer.
