Backpacks & Pick-up's fix.
By Tronko.

As almost everyone knows, there is a trick that allows to transport multiple resource backpacks in the back of a pickup truck. As you cant climb on the back of the pickup directly, you need to park the pickup next to something you can climb on, for example, a wooden fence, and jump in the back of the truck. Then, drop the backpack there. Repeat with another backpack and so on.

But then we have to deal with two issues:

Once the truck is loaded with the backpacks, if you drive forward, the backpacks stay in mid air. Seems like the physics engine is ignoring completely the backpacks. Actually what is happening is, when the backpack is loaded in the pickup it only interacts with the tires of the pickup, and nothing else.

The second issue is, if you are lucky and the backpack touches a rear tire, things seems to go fine until you start to drive a little faster. Then you will notice that the backpacks have the bad habit to slide off thru the walls of the pickup truck. If you stop the pickup to recover a dropped backpack, and no backpack is touching a rear tire, the backpacks will stay in mid air again like the first issue.

This little mod fixes both issues. The backpacks are now correctly physicalized.

Now you can carry up to 7 to 9 backpacks (in my play testings) at full speed in your prefered pickup (old & new). However, if you put a lot of backpacks in your pickup some will stack one in another. Bear in mind that the back of the pickup is not deep enough to hold stacked backpacks, so if you drive aggressively you will lose some eventually (like in real life)

It works with vanilla and Breakdown DLC, and there is no need to start a new game. Does not affects savegames.

Known issues:

Sometimes, if you leave a game with a pickup loaded with backpacks, after entering the game again, the backpacks will appear in the terrain, just under the pickup. This seems to to be noticeable when you load a game and the pickup is nearby the player and/or in the player's field of view. The engine seems to spawn in the game world the backpacks before the vehicles, so the backpacks doesn't collide with anything, and fall down freely.

How to install:

Extract directly into game folder:
..\State of Decay

After extracting you must have this file installed:
..\State of Decay\Game\scripts\entities\items\ul_rushsack.lua

Unistall:

Simply delete the file:
..\State of Decay\Game\scripts\entities\items\ul_rushsack.lua