we were there is Dec 2011. went through downtown, it wasn't too bad. though we pulled in after dinner, so went through the city around 6PM or so, and when we left it was morning of Jan 1, so a holiday.
Good Sam Life Members. Camping with two young children in a 2007 Pilgrim fifth wheel (278BHSS) pulled with a 2002 F350.
They just redid the cross town going through downtown Charleston which might make that portion a bit easier to deal with. They did a very nice job, a few lights but nothing hard to manuver through. This is the section between I26 and 171/Folly Road. Enjoy