I find these threads so funny.  We've been fulltime five years and DW will not use public facilities if we are near the fiver. We have camp hosted where she cleans the public use facilities, she still will not use them. I was a carpenter and did kitchen and bath remodels for many years and pulled toilets during those jobs, did not re-install that was the plumbers purview. Worked construction with nasty port a potties, hey ya gotta go ya gotta go. 
We stopped on our way to Alaska at Banff NP in Alberta, when pulling out we had to wait in line to dump. The guy in front of us put on gloves, nice and sanitary , while his wife filled the fresh water tank. When he was finished he called her over and proceeded to stick the fresh water hose into the slinky to rinse it, she then went back to filling the fresh water. That's gross! 
If OP doesn't want to use his facilities he should pull the potty and have storage for whatever.