I've done a lot of 3D-Work and the most complex was a 3d design of a substation for power distribution going in a really testy part of the downtown area here in Kansas City.
I agree that the plain packaged stuff that comes with AutoCAD isn't that great. So what I did was downloaded some image maps typically used for games like Doom, Halo, Max Payne, and the like and yanked out some stuff there and imported it into my AutoCAD renderning library. Tell ya what after playing with a few variables I had that baby looking pretty nice.
Anybody wants a picture of it just let me know!
I even contoured the parking lot, curb & gutter, street, and the grassy areas with trees and all kinds of stuff. I plotted out various perspectives of it depending on where you were staning, how you were looking and etc...was very cool.
Well when the Engineer took the samples to a meeting, they ended up picking a different spot (one not so testy) that the same guy owned...he was so impressed that he stole those images from the engineer!
The whole drawing file is about 50Mb in size but I did some screen captures of the finised rendering and saved them to jpegs.
Anyway...Sorry to ramble on.
But there might be some good ideas (in there somewhere) that might help if your boss is unwilling to spend money on special 3D software for one presentation.