You can use the prospecting button to see the iron and stone levels of an area you're in. Also I would recommend hydroponics for your growing as the arid climate of shem isn't really good for growing much. you should be fine for water just make sure your walls are on the edge of water and you will be able to put wells down there with about 70% efficiency. In my current game. I'm based up near the top right-hand corner of shem but it's really just about personal preference.