A cheap tracking system for your truck is an extra cell phone. Most plans let you get the phone for only $10.00 per month. And then you sign up for family locator and there you go. If you are parking in an area that you are concerned about, turn on the phone. To track it, you just log on the website and see where it's at.
Just remember to hide the phone. And it you expect to leave it there for an extended time, you may want to plug it in. Most vehicles have a power plug in the center console, or in the back of most pickups and SUV's . Out of sight.