We are still stuck figuring out what to do. Originally our van had a toilet Electra Magic® Model 80 RV but with no holding tank and 3 gallons of waste adds up quick so pumping out every couple days (no holding tank) would have been a headache.
Next we tried to DIY composting toilet and bought all the parts off etsy (This item is unavailable - Etsy). This was pretty easy to put together and setup and for what it’s worth, the parts were made well and worked well. We had a few problems with this. 1.) it was in our shower so it was hard to keep water out of it while sitting on it closed. 2.) With the diverter my wife for some reason could never hit the correct spot so she basically peed in the bucket anyway. That led to a lot of smells. I still look at the natures head toilet and wonder if it would work. I can’t fathom dropping $1k on it if it doesn’t work.
Right now we just find places to go to the bathroom, which is actually not that hard at all or if at night just take a pee behind a tree in the bushes. We are still contemplating what to do next for this, but we are leaning towards a standard toilet and putting a holding tank on. Pumping out is gross but we haven’t found any options so far that have not been gross. 1bag per poo then tossing it might be the way to go.
When we were sailors we had a thetford portable toilet with a 5 gallon waste tank. This was the worst of them all. Do not go this route. Hauling around 5 gallons of poo and pee to dump from one of those is terrible and they smell awfully bad after about a day.