You don't pack it out, the I ky time you pack it out is if you know you have to. It's one of those, you will know before hand kinda things.
As for shitting, unironically learn how to shit the right way. Dig a hole and squat down over it. If you can't squat properly, this is not uncommon for people who have never rchanneled their inner slav, dig your hole by a tree, grab into the tree for stability and squat and shit in the hole.
The lower your squat the better, because god made out bodies to be amazing, when squatting properly your ass cheeks actually spread apart and when you shit this way 9/10 time your hardly have to wipe, if you do, just out the to in the hole and bury it.
DONT shit next to a river or creek.