Hey,
I also use SU primarily for exhibition design work, so hope this may be useful.
For rendering I use Thea, which I've found offers the best balance between quality and speed in a deadline-driven environment.
As for drafting, it really depends on the level you need. For knocking out some quickly dimensioned elevations, Layout does the job, but for drafting from-scratch, I found it way too laborious (I do accept this may be my shortcoming, not SketchUp's).
For 2D drafting, I've moved over to NanoCad, which has a VERY Autocad-like interface, and more importantly is FREE, for the basic version which does everything I need. Between SU, Thea and NanoCad, I think I've got it covered π
cheers,
A