Yeah, it's that "almost free" that'll get ya!
So let's talk $.
CEB machines run around $1700 for a manually operated model, $3000 for air operated, and $6000-8000 for a hydraulic diesel machine. Assuming you have a road already in place to move equipment in. Assuming there is diesel fuel within a reasonable distance. Assuming you have the special permits for a non-standard building technique.
OK, say you already have the sawmill (cost ??). Which trees do you cut? You don't want to try to burn gum or softwood. What do you cut them with? How do you move the logs? Gonna buy a tractor? $10k, minimum.
You still have no electricity or running water. Dig a well? About $3500 depending on how far down they have to drill, plus inspections. Got a septic system? Will your ground perk? Occupancy permits? Bring electric in from the road? Better put it underground so the lines don't come down when the wind chill is -10! Big $$. Snow plow? You'll need a 4WD vehicle for Maine's fifth season, which is "Mud."
Gonna build a big greenhouse? How are you getting water to the hydroponics?
Who is actually going to do all the manual labor?
Etc., etc., etc.
Buying the land is the easy part. Realistically, start up costs for what you are describing are crazy high, not to mention a whole load of work. If you've never done construction, the $ amounts can be a big shock, and physical labor is tough, especially if you're not used to it. You'd do better to buy an old camp that already has working systems in place.
Really, not trying to shoot you down, just want to make sure you know what you're getting into. It's OK to have your head in the clouds as long as your feet are on the ground.