Dan, see my FlipPac thread. Our Thetford ensures relaxation.
http://americanadventurist.com/Forum/showthread.php?46-Dave-s-AT-FlipPac-Thread/page4
Dave, can you put tp in this thing or do you have to pack it out separate?
I'll answer since I'm also a Thetford user - TP is fine. You dump these directly into a toilet, so if the toilet can handle it, you're good to go. Thetford generally recommends "septic safe TP", (the kind that breaks down more easily in water), which is a smart move if you'll be dumping on the road and can't be sure of the capabilities of the system you're dumping into. For our use, we normally do shorter trips and dump in the loo at home, so our normal "house paper" gets used most of the time.
If there is an out house in the vicinity, I'll dump it in that before I leave if convenient.
mmm... burn barrels...