More specifically, give Kuu a marguerite for the Mog House upgrade. I believe there is one of these gardening Mithra kids in each major town, including Jeuno. They all want different flowers or items, but you need to give it to the girl in that town if you want to know the back routes.
Also, once you bring her a flower, she'll give you the ability to exit your mog house at any point where you can enter it (i.e. Port San d'Oria, South, North.).