Konnichiwa Martyr san,

Good thought.

These forums are already in the Forum Jump at the bottom (scroll down the entire list).

But another Forum Jump has been added too, you may like it: go to your control panel and select the LiteSkin in account option (update). You'll then see a Forum Jump for the Dungeon subforums on the mainpage. I'll apply this extra dropdown list to other skins if it's considered a good feature. Those are one ways though.

There's yet another way, available in every skin. You don't have to return to the Guild Index, but you can also enter the Dungeon Index (see the 'grey' Navigation Bar at the top please).