Okay!
Also, one of the best places for me to train and become stong is the Pride Lands; though I only am at places when their event is happening. Here are some great hotspots to train during their events:
Land of Dragons: After you reach the town that was burned to the ground, the pathway there is an exelent spot! A good place to train for the battle with Shan-Yu. In the first trip, try to reach level 18 (22 if you visited Beast Castle first). Second trip should be around level 40.
Beast's Castle: The West-Wing is a great place! An idea area to train for the battle with Xaldin! In the first trip, try and reach level 22 (18 if you visited here first). Second trip should be around level 43 for a good chance to survive the boss battle.
Timeless River: The Windows of Time are the perfect place to train once you have completed them. Try to get to level 28.
Agrabah: The main area in the Cave of Wonders can re-spawn the Heartless after entering another room. If you can, get to level 31 in the first trip, and level 48 during the second.
Pride Lands: The peak where Scar was fough will have millions of Rapid Thruster waiting to be killed! Also a hotspot for Simba's limit! It's a good idea that you train here until you reach level 51.
Space Paranoids: The IO Tower is a hotspot during the first visit. Just make sure that you enter the room where there is a save point and a ternimal, otherwise you will have to fight the Hostile Program and continue with the story; rest and save at the Pit Cell until you are around level 36. In the second trip, you won't have to worry about the story event anymore, so you can train at this hotspot until you reach level 55!