southeast from the atlanta metro area up to chattanooga.
make the core of atlanta a hot zone full of ghouls....hotlanta, include a high tech safe zone in atlanta for trade, intrigue, etc. that is accessible via underground access.
there are military bases around the city as well. plus it is the original home of the skunkworks, so secret armor and weapons research.
hospitals, colleges, and movie production for flavor and quests. it is the home of coca-cola, maybe a rival of nuka-cola common in the southern commonwealths.
six flags over georgia could be a neat place to include, the atlanta zoo too.
there are civil war historic sights throughout the southeast, so it might make for some sort of weird side quest. chattanooga is home to RC cola, moonpies, krystals, and is a center of river, rail, and road trade. it has its own hydroelectric dam, a feature common to several fallout games. the mountains around chattanooga overlook the city and the tennessee river, which runs through the city. civil war monuments, the incline, lake winnepasoka across the state line in fort oglethorpe georgia (yep that oglethorpe, the debter's colony settled by james oglethorpe during the early colonization of the country), and a railroad museum.
between the two cities there is farmlands, low mountains, lakes, rivers, and historic small towns for plenty of places to adventure into. throw in the usual gangs, tribals, super mutants, ghouls, and an old world faction like the enclave known as the council made up of the descendants of wealthy families that paid for their own vault.
nope, haven't thought about it at all.