This was pretty much done in the same way as making the chest , but since this was a modeling exercise for me I used a sphere with 14 segments. Deleted half of it, including the top and the side then carried on modeling. I guess depending on the shape of the object that you will make you have to use your own judgment as to which method you will use to model be it Mesh, Polygonal or what type of primitive to use. It's the same as when you model a phone lets say, you will do most of it, if not all with box modeling. If you are doing something more complex and organic then use Polygonal Modeling.
Stage Four: Making the insides
I had a good look at the reference picture for this one and decided that it would be best to use the hose primitive. Using the bend modifier and the FFD 2x2x2 toll I shaped the object into the desired form quickly and did the same for the rest of the body, as seen in this image. Making the rest of the body such as the out side shell for the arms, legs and feet were also done with primitives. For the legs I used a cylinder in which I deleted the top and the bottom when it was converted into a Polygonal model, copied this shape to use for the legs and hips, just changed the shape of it with the modifiers and moving vertices. Always looking at the reference picture to get the shape right. You can see in the image below, how simple the shape is when the mesh smooth is turned off. Mesh smooth is an art form in itself, if you have made the base model with little Polygons and when the Mesh Smooth modifier is turned on you get the same that you want. Then you have done the job with not too much effort.