Remove supply crates across all maps. Allow players to drive the pick-up with the supply crate on it.
Remove all other pick-ups spawned for the players from the map. Spawn a pick-up with a gun for the players at the beginning.
Make players be introduced into the game inside of the supply and gun pick-ups. In the future, introduce humvees for these roles.
Alternatively/additionally add a 'supply drop' support type.