In September/October we are doing a road trip throughout the East/South of America and have a final bit of our itinerary to work out. After having driven south via the Blue Ridge Parkway, we are picking up a car in Atlanta at lunch time on a Wednesday. We then plan to be in Memphis the following Monday, so need to fill in 5 days. My current idea is to drive to Charleston for 2/3 days and then back to Nashville for 2 days before driving to Memphis.
I'm worried that this is a lot of driving and perhaps I should leave Charleston for another trip.
We are a family from Australia with 2 children (9 and 11 years old).
Is there anything else we should consider between Atlanta and Memphis that makes more sense ?

I'd save Charleston for another trip; there's plenty to see between Atlanta and Memphis.

Chattanooga, Tennessee, is an interesting southern city. If you have any interest in the American Civil War, there are lots of battlefields between Atlanta and Memphis, including Chattanooga.

Since you've already driven down the Blue Ridge Parkway, I'll assume you've seen enough mountains.

You might want to leave Chattanooga and drive across northern Alabama and Mississippi. Some things of interest: Florence, Alabama, has Helen Keller's home and if you've ever seen The Miracle Worker, it's worth a stop.

Also near Florida is the birthplace of W. C. Handy, author of Saint Louis Blues and many other songs, including Beale Street Blues, named for a street in Memphis. Then Tupelo, MS., Elvis' boyhood home. If you're really into music, continue to Clarksdale, MS, to the Blues Museum, then north to Memphis.

Or you could go on to Nashville from Chattanooga and then follow the Natchez Trace Parkway south into Mississippi. It runs pretty close to Florence and right through Tupelo.

<After having driven south via the Blue Ridge Parkway, we are picking up a car in Atlanta at lunch time on a Wednesday.>

Not quite "getting this--you are driving on the BRP and THEN picking up a car in Atlanta
Why not just drive to Charleston and then on to Nashville and Memphis. Leave out Atlanta!!
Tell us the first part of your trip (on the east coast, I assume). Then we can better advise.

I live in Atlanta (a suburb of)and grew up in Chattanooga and I think they are both great cities for kiddos! Mine are the same ages as yours and they love the following in Atlanta: Coca Cola Museum, MLK's home and the center located there, walking food tour of Downtown Atlanta (called Atlanta Food Walks) which includes food, history, architecture, etc., College Football Hall of Fame, Centennial Olympic Park, Atlanta History Center, the Botanical Gardens...

In Chattanooga, there's Rock City, Ruby Falls and Lookout Mountain. The Aquarium is amazing (better, in my opinion, than the one in Atlanta), Coolidge Park, etc.

As much as I love Charleston, you can't do it all and I think your family would love a stop in Atlanta and Chattanooga (it's about a 90 min. drive between the two, depending on where you stay).

Sounds like an amazing trip!

I'm not clear on the logistics either - why go all the way to Atlanta to pick up a car when you've already had one on the parkway?

Would it make sense with the rest of your trip to do Blue Ridge -> [Asheville if you have time] -> Charleston -> [either Atlanta or Asheville] -> Nashville -> Memphis? Still a ton of driving, and maybe too much for your plans, but it's hard to know without having a better idea of your whole trip.

If you're married to Atlanta and this timeline, Chattanooga was my first thought as well. Plenty to do for kids and it's a great city.