on a previous ford with keyless entry remote, i removed the lock cylinders from the door handles and put in stainless steel carriage bolts.
i then bolted one of these to the inside of the frame rail with a spare remote wrapped in a rag and then a small ziploc bag
i never did need that remote but i knew it was there if i needed it. i figured that if both of my truck's batteries were to go completely flat i had bigger problems anyway and a tow truck driver can still get into the truck in 2 minutes with the right equipment. most thieves that target the superduty just carry a big hex shaft flat head screwdriver around with them and a pair of channel lock pliers to turn the lock cylinders.
after doing that my truck was never touched again. they would have had to break a window and that becomes too much of a heat score when they have cops drive past them in the middle of the night with the window wide open.
if they're just going to drag the truck away, there isn't much you can do about that. you could install line locks on all of the brake lines but those would drain your batteries within a couple of days.