Travel potty chairs: how useful?
I've mentioned this a couple times before but we always traveled with a potty chair (a regular stand alone potty chair), especially when we had five children six and under. It saved on finding a public bathroom fast when you have the trickle affect of one child needing to go and then on down the line. All we had to do was pull over, let them go, wipe, dump, spray clean and go again. For us it was much, much easier.
I have a fetish with public bathrooms and hated taking several children to the bathroom. It was a long drawn out process and some of them couldn't go poo on a public toilet (I can't, I have to be at home!) so traveling with a potty chair was very useful to us.