I too support the idea that you might be able to turn the engine over with a wrench. If you are not successful, remove the spark plug (or plugs) and pour in a couple ounces of PB Blaster, let sit overnight, then try again. If no luck, you might be able to free the piston by screwing in a long bolt inside the spark plug hole. If you break the piston, your engine was toast anyway.
I do wonder if your problem is something completely different. Maybe something with the generator portion. Maybe the starter, maybe something else. 211 hours is not a lot and given your oil level was proper, it just does not make sense that the engine has seized up.