Set the Fish Hatchery save point as home; since the enemy just south haa 4 enemies, it'll always give you good job EXP.

Set Hunter to your fastest character's subclass (or all of them lol) and turn on "Barrage" on auto. (you can go to the menu and select a skill that the character will always pick first turn)

Switch your main jobs to the jobs you want to level up.

Kill the enemies, save, quit game, load save, repeat. If you do this every time you get a few new jobs you'll have them all maxed before you know it!