From the MARTA to the venue to the hotels is no big deal - it's a very touristy area, and even if you're not with anyone, there are so many people coming and going that there's invariably a crowd of people to follow if you're uncomfortable by yourself.
It doesn't bother me, though; I live in Baltimore, which isn't a whole lot different from Atlanta. I'll waltz from the Fairfield to the Grenada at 2am with two large bottles of liquor in my arms and not think twice about it.
My first time down at the Atlanta venue I had the same fears as you. Jaime is right, the area where the venue is at everything is really close by to each other. If you want you can send me a message of where you are staying and I can help you navigate from there. You can send me a message here or to babs4_b@yahoo.com
There are lots of decent people at Progpower that will help you find your way!
Jaime: You better come visit us at the Granada girl!!!! And we'll skip over your way (ha ha - skip) and harrass you too!