Well you can even do it in plain AC using SEO and simple shapes.
At least the basic forms..
1.for start it seems that the main body of the cabin is the result of an intersection (SEOs) of two horizontal cylinders (crossing vertical in plan).
2.Then you need to subtract two cubes (or slabs) to create base and roof.
3. Create the same shape again using smaller radius cylinder so that you can have an internal (offset) cabin. This can be used to subtract the interior and thus create walls and interior empty space.
It depends on how deep into detailing you want to go.
HTH
Petros
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