I'd second what mmoe said -
I used AutoCAD from ~1985-2009 and was a huge evangelist, but it's not something that can be learned part-time or casually. Our rule of thumb was basically that somebody using it full-time, and making an effort to push their knowledge, could become reasonably proficient in a couple of years. Any less than that, IMHO, and you'd be scratching the surface.
Not to take anything away from it, but there are almost certainly easier and more affordable tools available for the casual user. For that matter, if you don't need fancy parametric or drawing capabilities, you might be better off just learning BobCAD itself, and avoiding the whole translation issue. Maybe you have some other compelling reason to stick with ACAD, but if you were just getting into 3D, then I'd seriously consider investing the effort into an easier tool. It sounds as if this might be a fairly part-time endeavour. Learning AutoCAD just to model and toolpath a few shapes might be analogous to using a pile-driver to drive tomato stakes in your garden.