I'm planning on driving from Charlotte, NC to Charleston, SC (via Columbia) in one day, mid-May. I'd prefer not to drive on the interstate all the time (I'd prefer none at all, but don't think I'll make it if I include stops), but also see some nice smaller towns along the way. Things I'd be interested in is meeting locals at quirky roadside attractions, town museums, quaint city centres, that sort of stuff.
Looking at the map, US Routes 321 and 21 appear to be options, but I'm not sure whether these are worth it in view of my interests (or which one would be best).
Does anyone have any suggestions as to the route that's nice to take? Any towns / highlights that I definitely shouldn't miss? And if I do one half via the interstate (either Charlotte>Columbia or Columbia>Charleston), which should I choose?