THIS!! Honestly, how helpless IS your husband. I like the idea of the round trip town car. Then all he has to do is manage to dress himself and get the luggage downstairs.
I would expect her to be capable of it, but I would actually WANT to spend that extra time with her, and I would drive her. It's what my mom would have done, even though I left home at 17 and could have done it on my own.
Now if you do take her, and come back and get your male family members, they had better nearly throw you a party in thanks! Shuttle service deserves payment, afterall.