I went with the Domes and Arches concept. You have a central Command area that also contains living areas. The outer four domes are your work areas, and engineering. I included a external garage, a comms array, and a fuel depot. Also the design allows for expansion with external airlocks on all four outer domes. these are also the main ways into the base. I figure the outer corridors will have some windows to look out, and make it so everyone is not bumping into each other.