Park with your grill close to something like a wall,ditch or anything that someone can't just get a tow dolly past. Park with the wheels turned left or right to full lock. Install one the disconnect switch ideas already stated in previous comments (I like the fused HEI to ground switch). Also having a manual transmission will help since a lot of people don't know how to drive one. In the end insurance to cover the vehicle about the best way to recover from it being stolen. Meth-heads have days days to set around and figure out ways to get something if they want to get it.