Baltimore in sept might be best Choice. NYcc is biggest but a madhouse and expensive to attend
If you are more south then Heroes in June would be a good choice
Atlanta in may/June is first time I'm setting up so can't comment
Thanks GAtor! I live in Virginia, so Baltimore is a great suggestion - only about 3 hours away. My nephew and I drove down to Richmond VA for a very small comic con in VA this weekend. On the drive - with his encouragement - I drilled him on the relevance of key Amazing Spiderman issues. What's the first appearance of Doc Oc? , etc.
Eventually, I'll scaffold him up on the GA side of things. He is a quick learner. Need to pull in the youger generation, especially for GA!