1. Encounter at the Waterfall
- Easy Enemies, fast encounters, great XP. Just Keep your Prorings on, and if you give everybody either Light Axes, Mage Staff, Thor's Hammer, Zeus Gauntlet etc, you can cream them all in one round and hardly suffer damage. Heal staff and helms if you hget weak. I went from lv. 27-32 there without hitting an INN once.

2. The Eye in the Ice Cave. ProRings make you invincible, so it's just a string of 800XP shots. Easy, fast, even, dar I say, fun?!?!?!

3. Warmech. The Sky Castle in general is great for levelling, but the Warmech requires guts. And the enemies there may be a little tougher than elsewhere. But They might give more XP.

4. Zombie Dragons in the Castle of ordeals. VERY easy kills with Light Axes and the Mage Staff. Every once in a while they'll get a crit hit, but usually that's a fantastic XP spot. But it takes a while to get there. But it's probably worth it.

That's all I can recall using, off hand, for good, quick, easy XP gain (except that Warmech ain't easy...)