I love Charleston -- and April is a wonderful time to go! It's not quite
too hot to be out walking the streets, peering into alley gardens or to
plantation homes, and the humidity will still be within tolerable levels.
The tea olives will be intoxicating and the flowers will be heavenly.
Check out the visitors center when you get into Charleston to see about tours -- by horse, by foot looking for the ghosts of the old city, Ft. Sumter harbor rides, nearly everything is at your disposal right there. If you've got some definate ideas about what you want to do, post 'em, and we'll try to get you going in the right direction.
As for hotels -- my parents stayed in the Lodge Alley Inn, and they loved it! It's right in the center of it all in the downtown district within easy walking distance of all the shops and historic districts of Charleston.
I don't have any links available at this time, but I'm sure that some of the other Ziners have the information at hand, since they've posted it a few times before.
Mandy Huffman Easley, SC