Might this guide help you setting up SheepShaver?

http://emaculation.com/doku.php/sheepshaver_setup

I sort of wrote it. If you run into some specific problems, maybe I can sort them out?

Edited to add:

Oh, and there is one for kegs, which is a nice way to emulate that IIgs:

http://www.emaculation.com/doku.php/kegs