Good luck everyone!
I wouldn't try too hard with printing any of 40 CFR. I had a number of actual printed volumes that I took with me to the exam, and it turned out there were a few questions that I could have answered with other volumes that I didn't bring, and nothing that I could have answered with the ones I brought. So it's probably not even worth attempting to guess which ones will help you, and better instead to have other references that either summarize the CFR or give specific technical guidance to topics.
As for what to do prior to the exam, just maybe read a few sections of your textbooks that you might feel shaky on. For me, the day before the exam I re-did parts of the NCEES sample exam. It only took me a few hours, since I had already done the problems before. It was basically just an exercise to keep my problem-solving sharp. Then I went out and had a good dinner and tried to relax....