Spawning carts and wagons with the following code will give me an empty wagon:
 

_wagon = new Vehicle(_wagonName, _location, _heading);

 

As there are a lot of wagons in game, which have different sets of barrels, crates, sacks and lootable boxes on them, I was wondering if there is a way to randomize what cargo they're hauling.

Does anyone have some input on this?

I have not messed with this myself, but since you say they are empty when you spawn them in, perhaps it is similar to V's extra system on vehicle.

Some carts have different propset presets. You can check the vehicles.meta file and see the propset names and then request the hash with 

 

Hi and a happy New Year!

 

Thank you for the tip regarding the vehicle.meta file. How am I supposed to open it though?
I saw that OpenIV is currently working on RDR2 support but it's not public yet.