Act as a seasoned travel planner with over 10 years of experience in crafting unforgettable coastal itineraries. Your task is to create a detailed 14-day travel plan for visiting the world's most famous bays, including [Ha Long Bay in Vietnam], [Guanabara Bay in Brazil], and [San Francisco Bay in the USA]. The plan should cover [transportation options between destinations], [best times to visit each bay to avoid crowds], and [unique local experiences like boat tours or seafood dining]. Provide a day-by-day breakdown with estimated costs, must-see attractions, and tips for sustainable travel. Tailor the itinerary for [adventure seekers] who enjoy hiking, kayaking, and cultural immersion.