I would spend one less day in Memphis and one more in New Orleans. There are quite a few decent restaurants in Memphis, but if I only were having one meal there, I'd definitely have the BBQ ribs at the Rendezvous. From there it is a very short walk to the Peabody Hotel to check out the lobby and, if your timing is good, you can watch the ducks "march" from the fountain in the lobby to the elevator to their "quarters" on the roof. Beale Street is also within walking distance from there.

One of my favorite old-school BBQ joints is Abe's BBQ in Clarksdale, which is at the intersection of Hwys 61 & 49, the "Crossroads" made famous by Robert Johnson. I highly recommend the Big Abe bbq pork sandwich. I have not been to the blues museum, but have heard good things about it from people who have.

The military park in Vicksburg is certainly worth a drive-through tour, and the museum in the Old Courthouse downtown is worth a look.

If I could only tour one antebellum home, it would be Longwood in Natchez. It's quite different from most, so if you see it, you might want to check out at least one more as well in either Natchez or Vicksburg.

In New Orleans, Canal Street is the main street downtown and deadends into the riverwalk where you can watch the river traffic. I know you can take a riverboat from there to the zoo and back, but am not sure what else is available there. I'd be sure to stay in or within short walking distance of the French Quarter. Driving in NO is a bit of a challenge and parking is always at a premium. Great food is shamelessly abundant. Two spots I'd not miss (both in the French Quarter) are Cafe du Monde for beignets and cafe au lait and Acme Oyster House for oysters, gumbo, po-boys, etc.

And I'd drive Hwy 61--at least from Clarksdale to Natchez, regardless of what your GPS tells you. I'm not sure of the best/most scenic routes from Memphis to Clarksdale and from Natchez to New Orleans, but 61 may be best there as well.

Have fun!