Your BF boarding pass will allow you into any of the CO Presidents Clubs. As stated, the one in Terminal E is the best. Unfortunately, there is no great public transportation option to quickly go into Houston and back to IAH.
If it were me, I would go to one of the nicer restaurants in Terminal E (like Pappadeuxs) and spend the rest of the time in the lounge. You will not be able to bring food into the club. The club has free wireless internet access and free drinks, so it is perfect for getting some work done.