I've driven down several times. Your best route is through Erie and Pittsburgh and south from there. CAA can give you a Triptick.
I don't like driving on dark American highways in areas I don't know very well so I pullover before sunset and in the summer, if I leave before 7:00 am I can almost get to Charlotte. This time of year you could stop somewhere along highway 77 which should have lots of places to pull over for the night. From there you may have only 6 more hours of driving the next day.
If you're golfing I'd say to stay in North Myrtle. It's closer to more courses and there's less traffic than in the downtown beach area. The downtown is busier and more touristy, but that may be what you want. The restaurants in North Myrtle are better, which is also where the better strip clubs (Crazy Horse and Thee Doll House) are. I'd recommend getting an efficiency unit so you can make your own breakfasts and any other meals you like so you don't have to eat restaurant food for 2 weeks. There's lots of supermarkets. My favourite restaurant is Umberto's (Italian, with big portions of good food in a boisterous atmosphere) at Barefoot Landing where they have a boardwalk along the intracoastal with wall to wall novelty stores and restaurants.
There's also a good outlet mall along highway 501 if you need to any shopping for yourself or to bring back gifts. Again, if you're a golfer, you'll love going into Martin's to shop for equipment and clothes. Great selection and some great prices, especially with the loonie doing so well. Make sure you check out prices here first though, just so you can properly compare. They've got way better stuff than Golftown.
I love Myrtle. It's a hoot.