You might need some mobile Orbital Habitats for that.
I did try a Battlestar Galactica sort of a start. I upped my engine, beam fire control speed and laser size from where it would normally be, then loaded everything into huge ships for cargo, cryo, maintenance, and troop ships. Had a few really large combat ships and some small escort but that was it. Made sure I wouldn't want to stay in my home system by making it have a disaster where the sun kept getting warmer, and two hostile nprs in the same system as well. An interesting game, but I did end up being wiped out by other races. They were lower tech, but as I only saved about 100 million population they just swarmed me under eventually.
Brian