Might want to post on the SC forum. Several guys there are familiar with the guides there. In the meantime I know the Pack boys guide out of Pack's Landing on the way way upper part of Lake Marion. https://www.facebook.com/Packs-Landing-117310945010616/
Blacks Camp further down Marion is home to some good guides also. http://www.blackscamp.com/
You didn't say what you were fishing for, but the Crappie, Bream, Shellcrackers and of course monster catfish will all be active in April.
Mark 1:17 ...I will make you fishers of men