I'm not sure what the EFF could put in such a guide. If the police believe you are involved in child pornography and get a warrant they will at a minimum come to your house and seize all of your computers to gather evidence. I can't imagine what exactly training the EFF can give people to prevent that from happening once the police show up.
And chances are that if you're tech savvy enough to run a Tor exit node that you'd rather not loose all of your computers for the several weeks or months it might take to get them back.
The EFF could advice people on the legal wall between corporations and individuals. Or how to start a corp. rent a tiny office and run a dedicated tor node from there.
I could be completely wrong, but it doesn't seem like you'd be much better off owning a corporation which is a front for child pornography (which is how it would be portrayed).
And chances are that if you're tech savvy enough to run a Tor exit node that you'd rather not loose all of your computers for the several weeks or months it might take to get them back.