I live in Tallahassee, FL. The mountains aren't that impressive around here, for sure.
Torreya St. Park is the best for hills around here. That said, head up to the Pinhoti Trail at Cheaha ST. Park. It's a great place to hike. It is actually the extreme foothills of the AT. I don't think it's ever been officially connected though.
The Florida Trail offers a completely different set of hiking challenges that can wear you out in places.