Atlanta without a car

Do you like sports? If so, check out the schedules ahead of time and see what's there. In addition to what you have listed, I would recommend the World of Coca Cola (no, really, it's a thing!) and the Centennial Olympic Park are a couple of other suggestions along with the Atlanta botanical Gardens. You may also want to check the schedule for the Fox Theater and see if there is anything going on (play or concert) while you are in town.

Midtown is a good location with good access to MARTA, the Atlanta "subway". You can use this to get around town as well as Uber. For MARTA, you can download an app that shows the schedule as well as how to get from place to place. Buy a Breeze card and add "trips" as needed. You will need a card for each person. I don't know too much about Midtown so I would check TripAdvisor for options there.

Another option is Buckhead (my company has offices here). It's a few stops north of Midtown on the MARTA (45 minutes from the airport). There are a number of hotels in the area of the MARTA station (Intercontinental, Embassy Suites, Courtyard, DoubleTree, Marriott). For restaurants, I would suggest Bones (really good steaks), BrickTops, Dantana's, Zinburger and Seven Lamps. Also, there is a Tesla dealership in Lennox Square Mall!

Check out The Highland Inn in the Virginia Highlands part of town. I think this may be what you are looking for. My sister lives 2 blocks away from it. You will be in the middle of a bunch of great restaurants and live music venues. This is a very popular area with the 30-45 year olds so don't worry about being the oldest one in a club like some cities. You'll be close to the 5 Points Marta Station that can get you to CNN. The Aquarium, World of Coke, and the new Civil Rights museum are all in the same area as CNN. The Jimmy Carter Library is very close by and the King Center isn't far from there. We have a very nice pedestrian pathway called the Beltline that links all these neighborhoods. You could start it at the Ponce City Market and walk it to the end at Krog Street Market. Great restaurants, coffee shops, etc in both. April is the peak of festival season around here too. Usually 2-4 different food, art, or music festivals going on in the parks. This part of town is where many of them are. I live on the Buckhead/Midtown border but probably spend more time down here on weekends. If I can help you with anything else, let me know! Atlanta is gorgeous in the Spring.

I go to Atlanta often... Sometimes with a car, but sometimes without. To save money you can stay near the airport and take the hotel shuttle back to the airport and take Marta downtown. It's so efficient. Last week I actually stayed at the Hotel Indigo which was a block away from the College Park station, so we did not even need the shuttle. I will sometimes book on Priceline (express deal). Go for a 3 or 4 star near the airport.

If you decide to get a car for a day you can take the drive out to Stone Mountain park. It's a beautiful park... A few areas are a little cheesy, but worth the visit.
Tons of great restaurants.

Another vote for visiting the Fox Theater if there is a show or concert that strikes your fancy. If price considerations rule out staying in the Midtown or Virginia Highlands area, staying close to the airport (as suggested) is a viable option and you can just "day trip" into the city proper.