We took a Carnival Cruise from New Orleans a couple years ago. We did not have a car so my information may be way off base.
The area is just beyond the French Quarter, the side streets are a little narrow, lots of one way streets, and the neighborhood is not real nice.
I would not bring my motorhome into this area.
Popular parking near the cruise terminal seems to be plenty secure and I wouldn't worry about parking a car there. I seem to recall a lot of open space parking in this section of town, but most is not particularly secure. I think I would pay the $16 and feel good that my car was okay when I returned.
Have a great trip, We loved cruising out of NO and hope to do it again.
Norm & Ellen Proud to be one of the HOOTS
2015 Newmar DutchStar 4369
If I knew retirement was so much fun, I would have done it in my twenties!