Call me naive or just plain stupid, but I don't lock up anything. It's my opinion more than likely if I lock something, it will bite me in the a** rather than impede the actions of a thief.
The door locks on my trailer are the same as countless others out there, yes even the supposedly special deadbolt. If I locked up my propane, the day I needed to unlock an empty bottle it would be freezing cold and raining, and the key would be safe and dry at home on a hook.
That's not to say I'm careless. I do cover up / hide valuables, including trying to keep my generator(s) out of sight when I'm away. But I'm not super worried, there's nothing that valuable on or in my trailer, and if I do get cleaned out, that's what insurance is for.