I recomend Final area(Crater)

Look in the swampy area with the suttle You will find movers and magic urns which giv A LOT of exp, money, and ap. (movers only giv ap i believe...-_-) If you need elixers use the W-item trick. If you don't have w-item than u can get elixers from other enemies in the area.
the Gigheeand master tonberry.