You'll enjoy the beaches and museums in Nessebar Old Town. You might want to make time for a stop at Church of Saint Sophia or Nessebar Old Town Beach.
While there might not be top attractions in Chaika, you can explore the larger area and discover places like Platinum Casino and Action Aquapark.
When in Rusalka, you can plan a visit to Sveti Vlas New Beach and Dinevi Marina, some noteworthy sights in the nearby area.