Some of the best places to train and level up are TWTNW, Pride Lands (lower levels) and Radiant Garden (Hollow Bastion). TWTNW is FILLED with enemies, that can get you easy, fast, experience. Pride Lands can not only give you good crystals, gems, stones, but are packed full with enemies especialy after you beat it the 2nd time. Then at the top of pride Rock...i'll just say...look there. Hollow Bastion can give you rare items, tons of Munny and theres Sephiroth, who, if you beat him you'll recieve Fenrir, the strongest weapon in all of Kingdom Hearts 2. Hope this "cheat" works for you!