I recently purchased a used Alaska 140 furnace that had the old style Triburner stoker units. That unit is now installed at my buddies trucking company in the shop. He removed a Harman Magnum (85K btu) that was not up to the task. His garage is 30 by 60 with no insulation and some areas where the ceiling is open to the metal roof above. It keeps his shop at 58* to 68* in single digit outside temps without any ductwork or the funrace working overly hard.
Bottom line is that the unit was under $1,200 used, throws a ton of heat and is as reliable as anything out there. If you decide to try and find an older used one I have a few tips for making it run better.
Since it throws a ton of heat it uses lots of coal at full output, but then you are close enough to cheap coal to make this the most economical solution to heating a large area.
As far as coal sources go if you have a way to transport a few tons at a time then there are sources in PA within 50 to a 100 miles of you that may be well worth the effort. Or if that is not an option checking with local stove dealers you can usually find out. I live in NE PA so I am not familiar with your area, but I'm sure some of the other members can help you out.
Hope this helps and good luck withyour search.