Thanks for this thread and all the info here. This isn't something I have had to worry about before but 2 of my girls are old enough to go with me on some longer trips now and I need to get something for the side of the trail.
My plan is the
Reliance Fold-To-Go, some
wag bags (or the Ozarks from Walmart posted earlier), and a
cheap pop-up shelter.
Not many people like the pop-up style tents but for a quick side of the road potty stop they seem ideal. For an overnight stay where we would setup the toilet and leave it for multiple uses, I would certainly want something with more structure and that can support a shower but setup time and space are more important for 5 minute potty breaks on the side of the trail. I can just hold the tent up if it is too windy when they are in there.