The mods I have done for years are battery disconnect switch...this serves 2 purposes, maint on the truck is a breeze because you don't have to remove battery cables, and finally long term security and storage...no battery drain.
the other is to wire a discreet switch, even keyed for that matter that is tied to the injector pump fuel solenoid....if you kill the 24v to the fuel solenoid on top of the IJ pump, that trucks not going anywhere under its own power.
an intruder cranking it would kill the batteries and may even fry the starter...but that truck ain't starting.
i install all my battery disconnects under the passenger seat, right next to the battery compartment facing Into the first aid kit compartment, you have to tilt the seat back to reach it...it is keyed. The switches are available at harbor freight or any auto store for like 15.00.
get a heavy duty model.