You miss out on a lot if you play in Sandbox Mode. A lot of locations don't appear, there's no way to get unique items like Pim's Navigation Device or the S&W Model 500, there are no volunteers, and you can't become a cannibal. Follow these steps to fix the no cannibalism issue.
Where[]
Files: IsoEngine\Caravan.class.asasm and Data\Item.class.asasm
How[]
Turning your caravan into cannibals has two parts: one to get human meat to appear and another to eat it.
Looting[]
In Caravan.class.asasm, find this line:
trait slot QName(PackageNamespace(""), "cannibal") value end
and change it to
trait slot QName(PackageNamespace(""), "cannibal") value True() end
This allows your caravan to loot human meat from the dead, as well as slaughter slaves for food. It does not allow you to eat the meat yet.
Eating[]
Human meat is represented by text string number 4777. In Item.class.asasm, the fastest way to find the item is to search for either 4777 in the line below pushstring "name" or the calories, 1800.
Once you've found it, add these lines:
pushstring "food" pushtrue
After you've added them, move down to the newobject line. Increase the value there by one (1) because of the additional argument.
This lets you eat human meat, but not loot it.
Problem[]
The downside of this code is it also turns everyone else into cannibals. Towns will consume human meat if you sell it. You may be the only supplier, but you risk displacing the towns' regular diets and lowering the prices of other foods at the market—look up the US Government's position in Wickard v. Filburn for a lengthier argument of the economics involved.