If you are concerned about the entry door, you first need to replace the door and frame with something stronger. You can then use long throw dead bolts at each corner.
Windows and vents can be strengthened with expanded metal on the inside, but you will lose the ability to slide windows and only be able to use crank style models.
Exterior storage doors are also weak and can easily be pried open or the frames bent. Rekeying the locks would be the most I would spend on them.
Dummy fuses in the truck will slow a thief that does not tow your rig away, but anything in the cab is easily taken by breaking a window.
It's hard to keep a low profile when you roll in with a TC, but keep exterior enticements to a minimum and expensive things always out of view.
