Forgot to comment on the Porta Potti problem. Most really light campers do not have toilets.
I bought a lightweight truck camper and reluctantly purchased a portable toilet for it. It has proved very useful. The tanks can be easily refilled at any faucet and the black water can be dumped into a regular or pit toilet if necessary.
We only use our toilet for liquid waste but that has been not problem for those quick nighttime needs. Real problem is the need to place or install in an open spot so privacy is definitely reduced.
Lightweight and approx $100-150 so you aren't paying a lot for the experiment.