We set up a 10 x 10 shelter next to tear. In one corner away from th tear I Curtain off a changing area with a PP in it for my wife to use at night. Clean it first thing in the morning and no odor problems.
Our porta potty is stored in the galley under the sink. When clean modern facilities are not available, we set it up in the tent that attaches to the back of the teardrop.
We found a really portable oneon Google. Like a camping stool with a plastic bag. I can use a bottle. Wife cannot. Naturally the best is the campgroung one.