Marie-Louise didn't want to go to Elba, even had her father and the British allowed it. By then--April 1814--Neipperg had already been dangled in front of her, and her dame d'honneur, that witch the duchesse de Montebello, influenced her to go to Vienna to get as far away from Napoleon as possible. M-L had the backbone of last week's spaghetti noodles, so off she went. I suspect she would have refused Elba outright had she been asked to go there.