So I wanted to mention these potty seats I found for potty training. We have two of them, and I’ve been on the side of the road using both of them in the back of the truck before. They fold up and come with a little carrying bag, small enough to put into a diaper bag (that’s why we have two, one for each diaper bag). They are the Kalencom 2-in-1 Potette Plus, the company is based in New Orleans. I only bring that up because it’s just east of Lafayette, LA, where my in-laws live.
They can be a potty by themselves, and you put this little bag in them and just throw it away after it has been used. Or you can fold the legs out into wings and they sit on a regular toilet seat. This is a whole lot better than holding a slow pooper’s hands (I’m looking at you, Andy) so he doesn’t fall into the porta-potty chemical poop bath. They’re somewhere are $10 each on amazon.com. After the first couple of uses I would have paid a lot more. It comes with some liners, but you should buy more, especially if you have lots of kids potty-training at the same time. In a pinch you might consider using a regular small plastic bags, but I seriously doubt those are going to be water tight. Better than nothing, though.
The only thing I’d add is to consider some potty protectors (the kind that cover an entire toilet, if you are a man you know why). I bought some Summer Infant ones, but haven’t had a chance to use them. I’d be perfectly find never having to use them, but I also know that if I need one I will have a really bad day if I don’t have it.