We have used the wag bags in our camper actually with great results. I did not want to use the black tank and have to clean it after one month of use.
I suggest some sort of Pett set up like everyone else has. I bought the cheap one for our non existent Rubicon trip. It is a folding fishing chair that uses the wag bags. The chair was $11 and the bags vary depending on the amount you but at a time.
Tent is optional