Well, down in the Charleston area, NASCAR was on several of the big country music stations, like Cat Country 107.5, and The Gator from Savannah. Then, MRN dropped 107.5 last year, and now, it is on a hard to hear classic country station, 950 AM, with the night races stuck on 950 and tiny 1450 WQNT.
The problem is that there are three networks that carry different races. To carry the Indianapolis race, for example, you also have to carry the Indy 500, and the hours of support coverage that the IMS radio network carries, and that is why that race gets less coverage on radio here than in other places.
Nationwide Series races are much more popular in the Kentucky and Tennessee area, because stock car racing is so popular there. I was in Nashville last year during a Nationwide race, and it seemed like every tiny AM country music station that wasn't carrying football was airing the Nationwide Series.
Craftsman Truck Series races are almost unheard of here, except for the very dedicated stations that carry every race.
If you live anywhere south of Raleigh, you will be able to hear most races on 95.7 WKML or 92.9 WEGX (which brings a good signal above Fayetteville).