Help me with leveling and map recommendations

[Raldo]

Did you try running dungeons repeatedly? Also, pick up the challenge log if you haven't (lv15ish quest by the Leve counter in Limsa). If you're in Limsa, the lv17ish FATEs would be in Western La Noscea. I would also suggest doing your hunting log, if you aren't. The duty roulette daily is also an excellent chunk of exp.

Quests are, for the most part, one-time-only things, so if you already did them on some other class, future classes will just have to grind dungeons/FATEs.