Hosting a 50+ person brunch - how do I handle bathroom logistics?

My cousin is getting married in Boca next month, and we offered to host the day-after brunch at our place. We're expecting about 50-60 people. We have a nice backyard, but our house only has two bathrooms. I'm already stressed about cooking for that many people, now I'm realizing the bathroom lines are going to be a disaster. Is it okay to actually rent portable bathrooms for a daytime event like a brunch, or is that overkill?