Check out projected curve with a sketch onto sketch option.
You will need to cut your model up some.
From help: "You can project a sketched curve onto a model face to
create a 3D curve. You can also create a 3D curve that represents
the intersection of two extruded surfaces generated by creating
sketches on two intersecting planes."
Once you have the curves I would suggest constructing the model
with multiple boundary surfaces. You might want to start with a
simpler model to learn surfacing with though.
From help: "You can project a sketched curve onto a model face to create a 3D curve. You can also create a 3D curve that represents the intersection of two extruded surfaces generated by creating sketches on two intersecting planes."
Once you have the curves I would suggest constructing the model with multiple boundary surfaces. You might want to start with a simpler model to learn surfacing with though.
I hope this helps.
Rob Stupplebeen