The Porta makes a good seat but emptying it is a nono. Use plastic bags and paper towels to create a virtual absorbant diaper. The end product will be about the same size as a diaper and is easily disposable with ur daily trash.

Having said that, the Porta potti is going to take up permenant space in your vehicle. It may be best to go with a handicap assist seat like this one. Or just go completely minimal with a space saving bucket that can also hold extra bags, tp, and paper towels while remaining completely innocuous.

Although, looking at it now, I don't feel comfortable with a permenant toilet seat in my rig (that I have to look at). Or anyone else for that matter. So it may be just as beneficial to go with a home depot 5gal bucket and possibly modify it with a pool noodle lol

I think , for emergencies, this is the way to go