I have been going to Myrtle Beach on golf trips for 23 years. Yes there is more traffic, even in the early AM as we head out to the course, but not enough to cause a jam. On the way back from the course, slow traffic isn't much of a concern. If we schedule 2 different courses, we make sure they are next to each other. We do not schedule courses on 501 on a Friday or Saturday.
All towns have stores opening and closing.
We only hit the mall if we forgot to pack something. If we shop, it it usually at an outlet or specialty area like Barefoot and usually only if a rainy day. We get drinks, snacks, etc. Of course we shop the golf stores and visit various bars and strip clubs. Occasionally we may go to a live music show or Legends in Concert.