Wow. A couple of days in San Antonio? A couple of days in New Orleans? You might just find yourself captured with these cities and feel the need to explore more. The best itinerary is one that "goes with the flow".
Are you in a rush with a deadline? The best part of RVing, IMHO, is the ability to change directions or sit in place on a whim.
Neat Civil war areas to visit are Vicksburg and Natchez Mississippi, Chickamauga in North Georgia near Tennessee, Kennesaw Georgia for the Southern Museum of Civil War and Locomotive History. This museum houses the famous train the General of the Great Locomotive Chase of 1862 Fame. (In high school I worked on the project that brought The General back to Kennesaw.) Closer to Marietta is the Kennesaw Mountain Battlefield Park, where fierce fighting occurred with Shermans army marching towards Atlanta. Of course there's Richmond (Va), Appamatox (Va), Gettysburg (Pa) Fredericksburg (Va) and Shiloh (Tn) among others.
In San Antonio you are pretty close to Fredericksburg in the Hill Country. Highly recommend a visit, especially if you like wine - lots of Texas Wineries in the Hill Country. Most have tasting rooms on the Main Street of Fredericksburg. :-) The also have the Nimitz museum of the Pacific War. First Class.
New Orleans is a lovely town with so much history. A few days is a must. I haven't been back since Katrina. Having been as close as Slidell the week after the hurricane, the stench of the toxic soup from that far away put me off. I'm not sure how long it would take for the toxicity to go away. But that's just me.