I'm doing that race as well. I did it two years ago and there were port-a-potties in the transition area as well as a couple along the run. I spent the last 10 miles of the bike route going *really* fast because I *really* had to pee but there was no way I was stopping on the bike leg. Since it is a two loop route for the run, by the time you might need it on the second lap, you'll know about where they are.