Since we drive ours daily we take several different precautions. One that I always use on every car is a hidden key operated switch that either kills the ignition, starter, or fuel pump. Sometimes at least 2 of those on one car. Even if the switch is found, it still takes a key so it's not that easy for a thief to deal with. I also don't park them where I can't watch them.
On out of town events after the above is done, I also take the battery out and inside the motel, then chain the hood shut. Very simple to attach a couple of small chain links to the upper hood latch bolts, and dangle them down below the core support where I can put a pad lock on it. Easily removed if you want to park and show the car with the hood up later.
After all is said and done, the only way anyone could steal the car is putting it on a hook.
None of this is fool proof but it slows them down and draws attention, 2 things a crook doesn't want. Sounds like effort, but really not that bad.
I've even gone as far as sleeping in the car. Take showers and the family beds down for the night, I crawl into the back seat and catch a few hours.
