(it's also worth mentioning that for my first 1.5 years in Atlanta, I couldn't even afford a car, so my options were limited to Piedmont Park and the Georgia Tech campus)
In rush hour traffic from the Atlantic Station area, according to Google Maps:
Grant Park: 26min drive Centennial Olympic Park: 15min drive (I did go there all the time but it's not really a park? plus tons of car noise nearby) Freedom Park: 34min drive Candler Park: 28min drive Chastain Park: 28min drive
I'd occasionally go to the park along Collier Road or to Memorial Park (both 15-20min drive in traffic), but both are surrounded by deadlocked rush hour traffic for most of the afternoon.
I think the lesson is maybe that I should've chosen to live in the Little 5 Points area or somewhere east of Piedmont, but that would mean sacrificing my ~5min bicycle commute to the Georgia Tech campus where I was going to school at the time.
In the end Atlanta's car culture really grated on me, so I left.
That said, I think Atlanta is on a positive trajectory. I'm excited to see how the Microsoft campus impacts the western part of the city. I imagine in 15-20 years it could be a really appealing city.
Traffic is really horrible in Atlanta but I was able to plan around it so that it didn’t bother me much. But I would never think of distance against rush hour unless I had a specific reason. So while it may suck to drive during rush hour to get to a park, just don’t do that. Traffic is dead at 6am and is fine until 330 or after 7. Even a block from Piedmont park, I don’t think I ever went there except mornings, evenings, and weekends. This is different from other cities where there’s just no getting around traffic.
Living in midtown (or anywhere) without a car is hard, but there’s lots of cities that also require cars but don’t have so many parks and outdoor stuff.
There’s definitely a car culture and that’s a downside, but there are lots of parks.