Bus, Train, Flight, I need to find cheap transportation to Allentown, PA or some place close to Atlanta, GA?

I am trying to find a cheap way to get form Allentown, PA or some place close to Atlanta, GA. Then from Atlanta to Fort Benning. I am going to my boyfriends graduation. And his family and I are trying to find a way to get there. Your help is appreciated. I need ideas, information, the websites you find info on...I search but I can't find anything that is understandable. Please please please help. :D