What you saw is the result of many, many hours of cutting & shaping, after decades of ACAD experience, so you're right in saying it isn't really that easy! (Been using ACAD since way before they added the ACIS kernel for 3D solid stuff...) My philosophy is to view modelling as a form of sculpture, taking basic "blocks" and carving them to reveal the finished shape. That can mean creating shapes purely to act as whittling tools by "subtracting" them from the main model, or it can mean approaching each piece from a direction that isn't very intuitive. One thing's sure though - you can NEVER get enough money to compensate for the time you put in!
That cab is a conversion set for a 1:64 die-cast model, done as a commission for 3D printing at Shapeways. Turns out there's quite a market for trucks and farm equipment! I hate doing cabs though, because they are all full of compound curves, which ACAD hates. The folks who made the real ones did it by carving huge blocks of clay at 1:1 scale with hand tools - now that's a job I'd love!
I have access to Inventor, which should
be a better modelling package, but I don't get on with it the same way I do with ACAD. And Blender only resides on my machine now so I can use some of its import/export functions - actually modelling with it is a nightmare! But there are lots of folks on SW who swear by it - go figure. Really high-end stuff like Solidworks, NX, and Catia are way beyond my reach.