Well... Sayu/Reina/etc... their family moved with them to Tokyo. Relatives and dad are down in Yamaguchi/Fukuoka, but Sayu lives with her mom and her brother (I think? Her sister has moved out), and Reina with her mom and her brother.
They talk a lot about how they don't meet their dads much and how when they go down there for work or something they often visit and blog about how much they've missed them. Pretty sure that's the case for... well, everyone who doesn't live in Tokyo/Yokohama/Saitama/Chiba - as those are all places it's fairly easy to get to/from quickly.