The front piece is pretty good though. That section can be thickened like this:

First the front edge is very slightly wiggly. To straighten that out I selected the end surface control points and aligned them to be exactly vertical:



Then Construct > Offset to make an offset surface to the inside:



Edit > Trim the offset with a centerline:



This can now be mirrored and joined:



I then put in blends down here:



Then lofts for the thin "side wall" strips and then joined those in to make a solid. Hope that helps give a demo of how to go about that part.

- Michael