Since I have a truck camper, my toilet and kitchen and bed travel with me.
It is hard to get much more convenient. My favorite example is traveling in the Lamar Valley of Yellowstone. I travel in the truck camper, pull over and use the toilet when needed. Lunch time I cook a quick meal and eat it at the side of the road watching the bison or other wildlife. Meanwhile the big rig travelers drive to the Lamar Valley in their toads. They have to use the outhouses that you can smell for a mile. Lunch is a sandwich or whatever. By mid to late afternoon, they are worn out and begin the drive back to the RV parks, mostly outside of Yellowstone. I typically take an afternoon nap, eat dinner and return as the sun is setting.