ETAV8R
Founder of D.E.R.P.
I use the items below - depending on the situation:
the Travel John (as recommended by seanz0rz)
Go -Girl (recommended by 98roamer)
and have a Pett for in camp with a enclosure for campgrounds that do not have bathrooms (recommend by others).
Exactly our set up. Between all three my lady is set. We also have an E-Tool (military shovel) and they work wonders if you know how to use them. Thank you USMC for the outdoor crapper training. When I showed my GF how to use the E-Tool she was so happy and amazed. Need privacy take it off the trail and out of sight. Carry on.