I create compartments out of cardboard and strapping tape. That way I build it to the trip. Carrying the stove and lantern inside? Create them separate compartments so they slide right back into their little homes, and everything hasn't crashed down and filled those voids. Fruit that you don't want mashed? Make a compartment the width of the oranges and apples (gc trip). Carrying lots of food for a gc trip? Multiple compartments so you empty one at a time and create usable empty space instead of just having the level go down. You can even break them down if you want, or modify them with duct tape.
I am a river, babe - I've got plenty of time, I don't know where I'm going, I'm just following the lines..... - "We are water" by Shaye