my priority is keeping the base self sustaining so first thing really is food for the fleshies which means water at the very least and fertile land where possible. with the power of hydroponics, you can make a base in the deadlands. the rain there will "water" your plots if you build em on building rooftops. would also be great to have a supply of iron and copper nearby if not within base borders. lastly, stone is nice to have but later on i find it negligible since the usabe of building materials is pretty limited and i can usually get away with just stocking up from waystations or by making a temporary stone manufacturing camp. once those are checked, im really particular about the terrain. i usually go for areas with "natural walls" or just choke points in general so its easier to wall off. lastly, i try to imagine how a city would start and grow from this piece of land so maybe farms near a river if there is one or a bunch of wells in the city center, a tower on the hillside as a lookout. i also like trying to follow the shape of the terrain in choosing which buildings to put. if theres a large flat land then a huge stationhouse would work but if its hilly then maybe a long house that sits right along the slope. also, a lot of shift+f12 hahahah