I picked Bay Harbor to try and escape the Sargassum problem impacting the Caribbean/ Atlantic shoreline. It worked... even though we stayed in July which is the worse month for Sargassum, because the hotel is on the island's leeward side there was no seaweed on the hotel's beach or bay! Just a totally chill, hidden gem, tropical paradise.
They have a dock you can swim off of in front of the hotel, there are kayaks free to use, free bicycles as well. We stayed on the top floor and the views are stunning, just be ready to climb the stairs.
Bay Harbor hotel is on the "north side" so you take a boat taxi to get to/ from the main part of Caye Caulker. The price is technically ~$5 Belize for a two way trip using the "northside water taxi" company although they hardly ever charged us for the ride. I thought taking the taxi was easy and fun and being separated from the town definitely made it quiet at the hotel. (Walking from the hotel into town including the ferry ride took less than 10 minutes). Also, there are a few restaurants and grocery store close, just down the street from the hotel.
Lastly, the manager Arielle is super competent and makes a great happy hour cocktail.