I was in Historic Charleston from 4/12/09 thru 4/15/09. The city and it people are beautiful, warm, and friendly. We learned while there that the prior week was quite busy with visitors for the Easter break. We experienced no crowds at all. The historic district is clean and very safe. If you have ever been to Boston or Salem, Charleston is similar in that you can walk form the visitors center on the north end to the Battery in the south end. The visitor's center is the first place you must start at. It is the most organized I have ever encountered. There you can schedule tours and book hotel rooms. Parking is limited on the streets but there are plenty of multilevel garages located strategically throughout the city at very good rates. Do not drive the city, the streets become narrow. Best way to experience it is to walk. Historic homes and landmarks are clearly marked. I just wish I had time to visit inside some of the homes and museums.
Highly recommended and to truly see it all it has to offer you need a full 5 days.