Regarding the zip lock plastic bag for TP - It took me a long time to get used to this, but on a trip to Yosemite with Wandering_Daisy (again Thank you for the great trip!) the ranger station had some suggestions that really helped:
1. use a freezer bag (kinda obvious, but...)
2. Use duct tape on the outside of the bag so you cannot see the contents.

Option #2 really helped me - sounds silly, but we all have some sort of hang-up... right?! (well I hope so anyways)

Additionally, I kept all of my... bodily function equipment in a small nylon bag - had my handiwipes, my digger, etc. Was non-obvious when I grabbed it and set out to find a private spot.