Even though some peeps like to take their ocean barges on the strip most people take smaller boats. Maybe see if you can stretch the length of the garages on the two to 30 feet or something to expand the market and go with that. It seems you would make more money. Use one yourself and rent the other. Use one and sell the other to pay for the other. Also depends on how long you want to keep them. For a long term investment two house are better even though individually they would sell for less. You already own the land so let's talk houses. Let's say it cost you 150k a house to build the two and in ten years they are worth 1 mil. Not figuring the loans or anything you have a 1.7 mil profit. Now just build one bigger one at a cost of 200k and in ten years it is worth 1.5 mil you only have a profit of 1.3 mil.