Doctors disagree on whether I've got colitis, a spastic colon, or nothing, so if I'm not in the same boat, I'm somewhere near it.
Exodus sucks pretty bad, and Louise and I have gotten out of it by volunteering for it. We guard one of the gates on that Monday, and we have our own portapotty there. When we leave on Tuesday, it's smooth sailing all the way. You might consider that as a way around the long line.
The new tactic for Exodus is called pulsing, and it looks like Playa Foot is going to check on potties for you. They'll stage cars for exit, so people don't sit there idling. It's the first year, so I have no idea what the details are. If they've got portapotties lined up for the staging area, you're good to go!
Good luck and have fun.