Another thing I've seen done is to take that spare key and hide it on the vehicle.... Use a stainless steel bolt, wing nut, and lock washer, drill a small hole somewhere under the truck, and wing-nut it in place, or.....

I've also seen people drill a hole in the key and run the license plate screw through it, sandwiching it between the plate and the bumper. Then, should you ever lock yourself out again, use a coin or screwdriver to unscrew the license plate bolt and free the key.

Those are my best suggestions....

-Joe