You have one free day between flights, a conference, or a longer safari, and the coast is right outside your hotel. That sounds easy until you see the distances. A beach may be 20 minutes away, while the famous island, reserve, or viewpoint takes two hours each way. I have learned to treat a single free day as a logistics problem first and a sightseeing problem second. The best Africa coastal day trips keep the main experience close, leave a large return buffer, and still work if June wind or rain changes the plan. Cape Town, Zanzibar, Mombasa, or Durban?…