Well well...the part of the game you have to go through now is basically a very long run in an immense dungeon. Don't forget to go in the Land of Eureka because the game's strongest weapons, jobs and spells are down there on the bottom.
Save when you are mid-way and don't waste your Elixirs, you have to have at least two left for your Sages right before you fight the Dark Cloud. Remember that the healing fountain in the Land of Eureka is the last you'll ever meet.
And watch out for the last four optional bosses, they're though.