We like to take back roads off I-77 to our DD in the Charleston area. Hopefully our next trip will involve some scenery as much of the route follows one of the few "green-dotted" aka scenic routes in SC in my Rand-McNally atlas.
This is in the eastern part of the state. Take US 601 east of Columbia (via US 76/378), SC 267 east to SC 6 east, turn left at Cross toward Pineville, then right on US 52 at St. Stephen's to Monck's Corner where the scenic route ends.
In the western part of the state from August GA to Anderson SC, twisting aroung to the NE to Chesnee/Mayo,you could drive SC 81 for quite awhile before taking SC 412 out of Starr to SC 187, right on SC 11, aka the Cherokee Foothills Nat'l Scenic Hwy out of Oakway, all the way around to the Cowpens Nat'l Battlefield.
These seem to be the 2 longest SC scenic routes, although there is another I found on my SC state map that goes from Exit 18 on I-20 and ends in Anderson.
Definitely get maps to better plan your routing. Hope this helps.