Buy a car Saturdays in a foreign city

I want to buy a car tomorrow. I drive my car to a far away city to a car dealer (car purchase on Saturdays possible, thousands of cars in the yard) and am determined to buy a car. (50% bar, 50% financing). My old car should stay there. That should be my dealer’s pleasure. An acquaintance said this is not possible. I imagine this: I drive there and get a short-term license plate or dealer’s license plate from the dealer and drive with the new car The letter will be faxed to my registration office or by express mail. Then I will register my car Monday or Tuesday. Does anyone have any experience here? I will ask my car dealer anyway, but I need to know if I have to get up in the morning.