PNWFJ80
You can just pull the fuel injection relay out of the fuse box under the hood each time you park, without that relay your truck isn't going anywhere. Plus the likelihood of a thief having one of those relays in his pocket is slim to none!
We do this with all of our race rig trucks when on the road, the amount of folks I know that have had their truck and trailer setups (with their race cars and tools) stolen never to be heard of again is disturbing!