My favorite quick "no steal it" move was a suggestion to leave the Transfer case in Neutral, potentially stumping non-4wheelers, and really unsuspecting drivers of any kind. Not a fail safe by any means but clever and quick. Fun to imagine as well.
Used in conjunction with a battery disconnect hidden a bit it might be all you need.
Honestly, Pulling the main ignition lead and stashing ( or just loosening ) it is a good preventative too.
No work = no steal unless they plan on towing it away...
I like the simple tricks over clubs and alarms and such. Esp. on old trucks.
Kindof a hijack, but maybe good advice to prevent more posts like that.
Sorry to hear of a real hijack wristy. Let us know if it comes home?