The Belfast area is a great place to live and offers lots of rental potential. The weekly and monthly rates would vary depending on the location. Waterfront would bring in higher rents especially in the summer months. Let me know what sort of property you are looking for and I can give you a better idea of what it would rent for.
I am an agent here on the MidCoast of Maine! The rental market here is pretty vibrant. There are a lot of Florida residents who maintain a rental unit here on the coast of Maine where they can stay when they are in town. Bill is correct in saying that it could not be considered your primary residence unless you spend a majority of your time in that home. When you are ready for a professional Buyer's Agent up here, give me a call...I would love to work with you to find the perfect property that will be attractive on the rental market. My cell number is (207) 975-9330.