Hi Daniel,
Can't offer good news.
Myrtle Beach is a beach with a ditch behind it...the Intracoastal Waterway (ICW). A man-made ditch (canal) through the pine trees. So no sound, no marsh, no estuaries.
The north end near Calabash and Little River offers good fishing, as does the south end around Garden City/Murrells Inlet. They are about 50 miles or more apart.
Another downer that time of the year is water temp...will still be in the mid to upper sixties, well off the magic 70 degree mark when the flounder and drum begin to show in decent numbers.
So...save the gas early next spring, wait another six weeks...and come down this way. But for fishing, not MB.
Hope this helps