Ive lived in SC for the past couple years and have fished all over the state. The Waccamaw river is the closest place to Myrtle Beach outside of ponds and such. It is a struggling bass fishery but you can catch some keepers there. If you have the time for a day trip go to the Santee Cooper lakes south of there. It will be a little bit of a drive but if you are going in May, find spawning flats with timber. The cypress trees are loaded with fry guarders and the females can still be roaming around. hope this helps and hope you have a great trip in a few months!