berlyda

There isn't supposed to be an event at Jirukala Stage at this point in the story. As you suspected, you're missing a ladder. You'll just have to keep fumbling around in the darkness, I'm afraid.

Go to Oceana Pier, south of Gearen City.

Focus Sash Endeavor (Quick) Attack Rattata

It's one of the houses in Goldenleaf, you'll know which one because it has 5 boxes in it in a line. I don't think this part is supposed to be a secret, so it should be ok to say it here.

As it happens, you use the ladder to get Narcissa's TM. Try looking around Amethyst Cave (hint: you'll need Surf and Dig, and be prepared for some tough battles).

There's another exit from the cave near the beginning that leads to a small clearing, head over there.

I'm going to have to swallow my pride and ask for the Odd Key location too. I've been searching for far too long, with no success. Can someone PM it to me please?

This was his estimate a few days ago:

I was just about to grab my HM slave from the PC when I noticed this. This is unbelievably useful, thank you so much Ame Now my Rhyperior can effectively have Surf, Strength and Rock Smash all at the same time, and it'll only take up one slot.

Aaah, I was waiting for this one My Chesnaught will be delighted.

Nah, I don't think it gets a boost, it's just guaranteed to have 110 base power regardless of whether an item is held.