I’ve been told by LEO friends that if the keys are out of the ignition and on the floor, you can’t be charged with DUI. Now, public intoxication is another story. But if you’re sleeping it off, they really have nothing.
The phrasing here is “Care and Control” of the vehicle. Keys in the car or your pocket, you’re done. It doesn’t matter whether you’re on the street or in a parking lot, either.
Putting the keys on top of a tire or in the trunk *might* work. Maybe.