According to the Geographic Midpoint Calculator website (refer to the link, below), the approximate halfway point of a road trip between Cleveland, Ohio, and Hilton Head, South Carolina, is 335 miles (i.e., 770 total miles), which is, roughly, near Wytheville, West Virginia.
Chesterfield VA is about halfway from Allentown to Myrtle Beach.
Tabors, VA
Hydro, Oklahoma.
Gatlinburg, Tennessee, is not the halfway point between Indianapolis, Indiana, and Myrtle Beach, South Carolina. The halfway point is generally closer to areas in Kentucky or Tennessee, but Gatlinburg is located further southeast from the direct route. While it is a popular tourist destination, it's not strategically located for a midpoint stop when traveling from Indianapolis to Myrtle Beach.
Cottondale, AL
Richmond, va
Emporia, VA
Santa Ana beach
Beckley, WV
If that's Myrtle Beach, it's in South Carolina. The halfway point is Enfield, North Carolina.
Raleigh,nc
Evergreen, AL. It's between Montgomery and Mobile.