Back at the Bottom
Hollow Bastion is a lot safer this time around without the likes of Maleficent and Riku waiting in the castle. Plus, you’ve already completed all of the puzzles, which makes returning to the Castle Chapel even easier. There will still be Heartless around, but you can handle them. The only thing in your way is a very long trip back to the top.
While still in the Rising Falls, you can activate the White Trinity in the fountain where you lost your Keyblade to Riku to reveal a Treasure Chest. Proceed all the way back up to the Castle Chapel using the same route you used the last time you were here. Nothing relevant to the story happens until you get there.