I also sometimes will put the truck in 4-wheel drive when I park it. that way, you cant just pick the back up with a wrecker and drive off (just make sure you put it in 4-wheel while you are still moving so the CAD has a chance to lock in).
Actually, I have seen that done and it stopped me, um, never.
I used to do some repo work and it's alot easier with a wrecker than you can imagine.
So, even with the front locked up, or the rear, doesn't matter. I would drag it down the street and throw straps and chains on it down the road. If I felt I was in the clear (usually long after the tires had flat spotted) I would get into the vehicle and select the gear that worked best. I almost never dollied. And If I had the combo flat/ drag, I could snatch the vehicle, drag it done the street then drag it onto the bed where I felt safe.
Truth is, if the want it, it is thiers. A good alarm system will stop the lesser crooks. Adding a battery for the alarm is a good idea, even under the hood. Motorcycle battery in a box bolted to the frame works ok. Also, strobes in the vehicle attract visual attention if anyone looks out the window to see whos alarm is sounding. Don't forget those pain generator sirens in the cab.
Simple kill switches work and can be placed almost anywhere. Magnet switches are only good if you can deactivate them and still look natural. Most crooks that are looking for a specific vehicle can afford to case it out for a day or two.
Changing the locks and covering the VIN is the first/ best things to do. Add a simple kill switch, and you are started. A relay run to a power ball valve in the fuel line is a doozie too.
Dave