Go Virtual Garage and spawn the Offroader. Im quite sure the door is optional. When you spawn a Offroader its usually random if he has doors or other stuff like backpacks.

Thanks I never tried virtual garage before, it seems very buggy though.

Not at all. Its for missionmakers to make vehicles look better. For example a Offroader without doors for a Guerilla mission.

Only tried it once and got the following issues.

[
_veh,
["guerilla_03",1]
["HideBackpacks",0,"HideBumper2",0,"HideConstruction",0,"Proxy",0,"Destruct",0]
] call BIS_fnc_initVehicle;

missing , after ["guerilla_03",1]

If there was a unit in cargo it crashed the code so I removed that.

And the gunner spawns on foot not in the gunner position.

I know it's work in progress so I'm not too bothered, I can at least spawn with the doors now.

As this is Guerrilla Offroad, sometimes it might not have driver door :) This is by design, not a bug.